Commit graph android_kernel_sony_sdm845/kernel/panic.c
Message SHA1
BACKPORT: locking/refcount: Create unchecked atomic_t implementation
Many subsystems will not use refcount_t unless there is a way to build the
kernel so that there is no regression in speed compared to atomic_t. This
adds CONFIG_REFCOUNT_FULL to enable the full refcount_t implementation
which has the validation but is slightly slower. When not enabled,
refcount_t uses the basic unchecked atomic_t routines, which results in
no code changes compared to just using atomic_t directly.

Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: David S. Miller <davem@davemloft.net>
Cc: David Windsor <dwindsor@gmail.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Elena Reshetova <elena.reshetova@intel.com>
Cc: Eric Biggers <ebiggers3@gmail.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Hans Liljestrand <ishkamiel@gmail.com>
Cc: James Bottomley <James.Bottomley@hansenpartnership.com>
Cc: Jann Horn <jannh@google.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Manfred Spraul <manfred@colorfullife.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Serge E. Hallyn <serge@hallyn.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: arozansk@redhat.com
Cc: axboe@kernel.dk
Cc: linux-arch <linux-arch@vger.kernel.org>
Link: http://lkml.kernel.org/r/20170621200026.GA115679@beast
Signed-off-by: Ingo Molnar <mingo@kernel.org>

UPSTREAM: locking/refcounts: Add missing kernel.h header to have UINT_MAX defined

Fix header dependency.

Suggested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1487855374-21993-1-git-send-email-elena.reshetova@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

UPSTREAM: locking/refcount: Add refcount_t API kernel-doc comments

Signed-off-by: David Windsor <dwindsor@gmail.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: elena.reshetova@intel.com
Cc: kernel-hardening@lists.openwall.com
Link: http://lkml.kernel.org/r/1489160052-20293-1-git-send-email-dwindsor@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

UPSTREAM: locking/refcounts: Change WARN() to WARN_ONCE()

Linus noticed that the new refcount.h APIs used WARN(), which would turn
into a dmesg DoS if it triggers frequently on some buggy driver.

So make sure we only warn once. These warnings are never supposed to happen,
so it's typically not a problem to lose subsequent warnings.

Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Elena Reshetova <elena.reshetova@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/CA+55aFzbYUTZ=oqZ2YgDjY0C2_n6ODhTfqj6V+m5xWmDxsuB0w@mail.gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

UPSTREAM: locking/refcounts: Use atomic_try_cmpxchg()

Generates better code (GCC-6.2.1):

  text        filename
  1576        defconfig-build/lib/refcount.o.pre
  1488        defconfig-build/lib/refcount.o.post

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

UPSTREAM: refcount: change EXPORT_SYMBOL markings

Now that kref is using the refcount apis, the _GPL markings are getting
exported to places that it previously wasn't.  Now kref.h is GPLv2
licensed, so any non-GPL code using it better be talking to some
lawyers, but changing api markings isn't considered "nice", so let's fix
this up.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

UPSTREAM: locking/refcounts: Out-of-line everything
Linus asked to please make this real C code.

And since size then isn't an issue what so ever anymore, remove the
debug knob and make all WARN()s unconditional.

Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dwindsor@gmail.com
Cc: elena.reshetova@intel.com
Cc: gregkh@linuxfoundation.org
Cc: ishkamiel@gmail.com
Cc: keescook@chromium.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

UPSTREAM: locking/refcount: Remove the half-implemented refcount_sub() API

CONFIG_REFCOUNT_FULL=y (correctly) does not provide a refcount_sub(),
which should not be part of proper refcount design patterns.

Remove the erroneous extern and the later !CONFIG_REFCOUNT_FULL
accidental implementation.

Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: Elena Reshetova <elena.reshetova@intel.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: 29dee3c03abc ("locking/refcounts: Out-of-line everything")
Link: http://lkml.kernel.org/r/20170701180129.GA17405@beast
Signed-off-by: Ingo Molnar <mingo@kernel.org>

UPSTREAM: locking/refcounts, x86/asm: Implement fast refcount overflow protection

This implements refcount_t overflow protection on x86 without a noticeable
performance impact, though without the fuller checking of REFCOUNT_FULL.

This is done by duplicating the existing atomic_t refcount implementation
but with normally a single instruction added to detect if the refcount
has gone negative (e.g. wrapped past INT_MAX or below zero). When detected,
the handler saturates the refcount_t to INT_MIN / 2. With this overflow
protection, the erroneous reference release that would follow a wrap back
to zero is blocked from happening, avoiding the class of refcount-overflow
use-after-free vulnerabilities entirely.

Only the overflow case of refcounting can be perfectly protected, since
it can be detected and stopped before the reference is freed and left to
be abused by an attacker. There isn't a way to block early decrements,
and while REFCOUNT_FULL stops increment-from-zero cases (which would
be the state _after_ an early decrement and stops potential double-free
conditions), this fast implementation does not, since it would require
the more expensive cmpxchg loops. Since the overflow case is much more
common (e.g. missing a "put" during an error path), this protection
provides real-world protection. For example, the two public refcount
overflow use-after-free exploits published in 2016 would have been
rendered unexploitable:

  http://perception-point.io/2016/01/14/analysis-and-exploitation-of-a-linux-kernel-vulnerability-cve-2016-0728/

  http://cyseclabs.com/page?n=02012016

This implementation does, however, notice an unchecked decrement to zero
(i.e. caller used refcount_dec() instead of refcount_dec_and_test() and it
resulted in a zero). Decrements under zero are noticed (since they will
have resulted in a negative value), though this only indicates that a
use-after-free may have already happened. Such notifications are likely
avoidable by an attacker that has already exploited a use-after-free
vulnerability, but it's better to have them reported than allow such
conditions to remain universally silent.

On first overflow detection, the refcount value is reset to INT_MIN / 2
(which serves as a saturation value) and a report and stack trace are
produced. When operations detect only negative value results (such as
changing an already saturated value), saturation still happens but no
notification is performed (since the value was already saturated).

On the matter of races, since the entire range beyond INT_MAX but before
0 is negative, every operation at INT_MIN / 2 will trap, leaving no
overflow-only race condition.

As for performance, this implementation adds a single "js" instruction
to the regular execution flow of a copy of the standard atomic_t refcount
operations. (The non-"and_test" refcount_dec() function, which is uncommon
in regular refcount design patterns, has an additional "jz" instruction
to detect reaching exactly zero.) Since this is a forward jump, it is by
default the non-predicted path, which will be reinforced by dynamic branch
prediction. The result is this protection having virtually no measurable
change in performance over standard atomic_t operations. The error path,
located in .text.unlikely, saves the refcount location and then uses UD0
to fire a refcount exception handler, which resets the refcount, handles
reporting, and returns to regular execution. This keeps the changes to
.text size minimal, avoiding return jumps and open-coded calls to the
error reporting routine.

Example assembly comparison:

refcount_inc() before:

  .text:
  ffffffff81546149:       f0 ff 45 f4             lock incl -0xc(%rbp)

refcount_inc() after:

  .text:
  ffffffff81546149:       f0 ff 45 f4             lock incl -0xc(%rbp)
  ffffffff8154614d:       0f 88 80 d5 17 00       js     ffffffff816c36d3
  ...
  .text.unlikely:
  ffffffff816c36d3:       48 8d 4d f4             lea    -0xc(%rbp),%rcx
  ffffffff816c36d7:       0f ff                   (bad)

These are the cycle counts comparing a loop of refcount_inc() from 1
to INT_MAX and back down to 0 (via refcount_dec_and_test()), between
unprotected refcount_t (atomic_t), fully protected REFCOUNT_FULL
(refcount_t-full), and this overflow-protected refcount (refcount_t-fast):

  2147483646 refcount_inc()s and 2147483647 refcount_dec_and_test()s:
		    cycles		protections
  atomic_t           82249267387	none
  refcount_t-fast    82211446892	overflow, untested dec-to-zero
  refcount_t-full   144814735193	overflow, untested dec-to-zero, inc-from-zero

This code is a modified version of the x86 PAX_REFCOUNT atomic_t
overflow defense from the last public patch of PaX/grsecurity, based
on my understanding of the code. Changes or omissions from the original
code are mine and don't reflect the original grsecurity/PaX code. Thanks
to PaX Team for various suggestions for improvement for repurposing this
code to be a refcount-only protection.

Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: David S. Miller <davem@davemloft.net>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Elena Reshetova <elena.reshetova@intel.com>
Cc: Eric Biggers <ebiggers3@gmail.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: Hans Liljestrand <ishkamiel@gmail.com>
Cc: James Bottomley <James.Bottomley@hansenpartnership.com>
Cc: Jann Horn <jannh@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Manfred Spraul <manfred@colorfullife.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Serge E. Hallyn <serge@hallyn.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: arozansk@redhat.com
Cc: axboe@kernel.dk
Cc: kernel-hardening@lists.openwall.com
Cc: linux-arch <linux-arch@vger.kernel.org>
Link: http://lkml.kernel.org/r/20170815161924.GA133115@beast
Signed-off-by: Ingo Molnar <mingo@kernel.org>

UPSTREAM: locking/refcounts: Implement refcount_dec_and_lock_irqsave()

There are in-tree users of refcount_dec_and_lock() which must acquire the
spin lock with interrupts disabled. To workaround the lack of an irqsave
variant of refcount_dec_and_lock() they use local_irq_save() at the call
site. This causes extra code and creates in some places unneeded long
interrupt disabled times. These places need also extra treatment for
PREEMPT_RT due to the disconnect of the irq disabling and the lock
function.

Implement the missing irqsave variant of the function.

Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r20180612161621.22645-4-bigeasy@linutronix.de

[bigeasy: s@atomic_dec_and_lock@refcount_dec_and_lock@g]

UPSTREAM: locking/refcounts: Include fewer headers in <linux/refcount.h>

Debloat <linux/refcount.h>'s dependencies:

- <linux/kernel.h> is not needed, but <linux/compiler.h> is.
- <linux/mutex.h> is not needed, only a forward declaration of "struct mutex".
- <linux/spinlock.h> is not needed, <linux/spinlock_types.h> is enough.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Link: https://lkml.kernel.org/lkml/20180331220036.GA7676@avx2
Signed-off-by: Ingo Molnar <mingo@kernel.org>

UPSTREAM: locking/refcount: Always allow checked forms

In many cases, it would be useful to be able to use the full
sanity-checked refcount helpers regardless of CONFIG_REFCOUNT_FULL,
as this would help to avoid duplicate warnings where callers try to
sanity-check refcount manipulation.

This patch refactors things such that the full refcount helpers were
always built, as refcount_${op}_checked(), such that they can be used
regardless of CONFIG_REFCOUNT_FULL. This will allow code which *always*
wants a checked refcount to opt-in, avoiding the need to duplicate the
logic for warnings.

There should be no functional change as a result of this patch.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Acked-by: Kees Cook <keescook@chromium.org>
Acked-by: Will Deacon <will.deacon@arm.com>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20180711093607.1644-1-mark.rutland@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

UPSTREAM: locking/atomic: Introduce atomic_try_cmpxchg()

Add a new cmpxchg interface:

  bool try_cmpxchg(u{8,16,32,64} *ptr, u{8,16,32,64} *val, u{8,16,32,64} new);

Where the boolean returns the result of the compare; and thus if the
exchange happened; and in case of failure, the new value of *ptr is
returned in *val.

This allows simplification/improvement of loops like:

	for (;;) {
		new = val $op $imm;
		old = cmpxchg(ptr, val, new);
		if (old == val)
			break;
		val = old;
	}

into:

	do {
	} while (!try_cmpxchg(ptr, &val, val $op $imm));

while also generating better code (GCC6 and onwards).

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

UPSTREAM: locking/atomic: Fix atomic_try_cmpxchg() semantics

Dmitry noted that the new atomic_try_cmpxchg() primitive is broken when
the old pointer doesn't point to the local stack.

He writes:

  "Consider a classical lock-free stack push:

    node->next = atomic_read(&head);
    do {
    } while (!atomic_try_cmpxchg(&head, &node->next, node));

  This code is broken with the current implementation, the problem is
  with unconditional update of *__po.

  In case of success it writes the same value back into *__po, but in
  case of cmpxchg success we might have lose ownership of some memory
  locations and potentially over what __po has pointed to. The same
  holds for the re-read of *__po. "

He also points out that this makes it surprisingly different from the
similar C/C++ atomic operation.

After investigating the code-gen differences caused by this patch; and
a number of alternatives (Linus dislikes this interface lots), we
arrived at these results (size x86_64-defconfig/vmlinux):

  GCC-6.3.0:

  10735757        cmpxchg
  10726413        try_cmpxchg
  10730509        try_cmpxchg + patch
  10730445        try_cmpxchg-linus

  GCC-7 (20170327):

  10709514        cmpxchg
  10704266        try_cmpxchg
  10704266        try_cmpxchg + patch
  10704394        try_cmpxchg-linus

From this we see that the patch has the advantage of better code-gen
on GCC-7 and keeps the interface roughly consistent with the C
language variant.

Reported-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Fixes: a9ebf306f52c ("locking/atomic: Introduce atomic_try_cmpxchg()")
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Sorayukii <sorayukii69@gmail.com>

Peter Zijlstra   authored and   Sorayukii   commited 2026-05-15 17:54:59 +07:00
f12e55866d
Merge branch 'android-4.9-q' of https://android.googlesource.com/kernel/common into HEAD
* 'android-4.9-q' of https://android.googlesource.com/kernel/common: (2014 commits)

 Conflicts:
	arch/arm64/kernel/psci.c
	arch/arm64/mm/mmu.c
	drivers/gpu/drm/drm_property.c
	drivers/hid/hid-core.c
	drivers/pinctrl/qcom/pinctrl-spmi-gpio.c
	drivers/thermal/thermal_core.c
	drivers/usb/dwc3/core.c
	drivers/usb/host/xhci.c
	fs/f2fs/segment.c
	fs/f2fs/super.c
	include/linux/libfdt_env.h
	include/trace/events/sched.h
	kernel/locking/spinlock_debug.c
	kernel/sched/core.c
	kernel/time/hrtimer.c
	net/wireless/util.c

Change-Id: I39072f45a8dc42a7bbe29eb52ed48a15c028869c

Bruno Martins   commited 2020-02-09 12:03:23 +00:00
e046a7aad3
This is the 4.9.197 stable release
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Merge 4.9.197 into android-4.9-q

Changes in 4.9.197
	KVM: s390: Test for bad access register and size at the start of S390_MEM_OP
	s390/topology: avoid firing events before kobjs are created
	s390/cio: avoid calling strlen on null pointer
	s390/cio: exclude subchannels with no parent from pseudo check
	KVM: nVMX: handle page fault in vmread fix
	ASoC: Define a set of DAPM pre/post-up events
	powerpc/powernv: Restrict OPAL symbol map to only be readable by root
	can: mcp251x: mcp251x_hw_reset(): allow more time after a reset
	crypto: qat - Silence smp_processor_id() warning
	usercopy: Avoid HIGHMEM pfn warning
	timer: Read jiffies once when forwarding base clk
	watchdog: imx2_wdt: fix min() calculation in imx2_wdt_set_timeout
	ieee802154: atusb: fix use-after-free at disconnect
	cfg80211: initialize on-stack chandefs
	ima: always return negative code for error
	fs: nfs: Fix possible null-pointer dereferences in encode_attrs()
	9p: avoid attaching writeback_fid on mmap with type PRIVATE
	xen/pci: reserve MCFG areas earlier
	ceph: fix directories inode i_blkbits initialization
	ceph: reconnect connection if session hang in opening state
	drm/amdgpu: Check for valid number of registers to read
	thermal: Fix use-after-free when unregistering thermal zone device
	fuse: fix memleak in cuse_channel_open
	sched/core: Fix migration to invalid CPU in __set_cpus_allowed_ptr()
	kernel/elfcore.c: include proper prototypes
	tools lib traceevent: Do not free tep->cmdlines in add_new_comm() on failure
	perf tools: Fix segfault in cpu_cache_level__read()
	perf stat: Fix a segmentation fault when using repeat forever
	perf stat: Reset previous counts on repeat with interval
	crypto: caam - fix concurrency issue in givencrypt descriptor
	coresight: etm4x: Use explicit barriers on enable/disable
	cfg80211: add and use strongly typed element iteration macros
	cfg80211: Use const more consistently in for_each_element macros
	nl80211: validate beacon head
	ASoC: sgtl5000: Improve VAG power and mute control
	panic: ensure preemption is disabled during panic()
	USB: rio500: Remove Rio 500 kernel driver
	USB: yurex: Don't retry on unexpected errors
	USB: yurex: fix NULL-derefs on disconnect
	USB: usb-skeleton: fix runtime PM after driver unbind
	USB: usb-skeleton: fix NULL-deref on disconnect
	xhci: Fix false warning message about wrong bounce buffer write length
	xhci: Prevent device initiated U1/U2 link pm if exit latency is too long
	xhci: Check all endpoints for LPM timeout
	usb: xhci: wait for CNR controller not ready bit in xhci resume
	xhci: Increase STS_SAVE timeout in xhci_suspend()
	USB: adutux: remove redundant variable minor
	USB: adutux: fix use-after-free on disconnect
	USB: adutux: fix NULL-derefs on disconnect
	USB: adutux: fix use-after-free on release
	USB: iowarrior: fix use-after-free on disconnect
	USB: iowarrior: fix use-after-free on release
	USB: iowarrior: fix use-after-free after driver unbind
	USB: usblp: fix runtime PM after driver unbind
	USB: chaoskey: fix use-after-free on release
	USB: ldusb: fix NULL-derefs on driver unbind
	serial: uartlite: fix exit path null pointer
	USB: serial: keyspan: fix NULL-derefs on open() and write()
	USB: serial: ftdi_sio: add device IDs for Sienna and Echelon PL-20
	USB: serial: option: add Telit FN980 compositions
	USB: serial: option: add support for Cinterion CLS8 devices
	USB: serial: fix runtime PM after driver unbind
	USB: usblcd: fix I/O after disconnect
	USB: microtek: fix info-leak at probe
	USB: dummy-hcd: fix power budget for SuperSpeed mode
	usb: renesas_usbhs: gadget: Do not discard queues in usb_ep_set_{halt,wedge}()
	usb: renesas_usbhs: gadget: Fix usb_ep_set_{halt,wedge}() behavior
	USB: legousbtower: fix slab info leak at probe
	USB: legousbtower: fix deadlock on disconnect
	USB: legousbtower: fix potential NULL-deref on disconnect
	USB: legousbtower: fix open after failed reset request
	USB: legousbtower: fix use-after-free on release
	staging: vt6655: Fix memory leak in vt6655_probe
	iio: adc: ad799x: fix probe error handling
	iio: light: opt3001: fix mutex unlock race
	efivar/ssdt: Don't iterate over EFI vars if no SSDT override was specified
	perf llvm: Don't access out-of-scope array
	perf inject jit: Fix JIT_CODE_MOVE filename
	CIFS: Gracefully handle QueryInfo errors during open
	CIFS: Force revalidate inode when dentry is stale
	CIFS: Force reval dentry if LOOKUP_REVAL flag is set
	kernel/sysctl.c: do not override max_threads provided by userspace
	staging: fbtft: Stop using BL_CORE_DRIVER1
	Staging: fbtft: fix memory leak in fbtft_framebuffer_alloc
	MIPS: Disable Loongson MMI instructions for kernel build
	Fix the locking in dcache_readdir() and friends
	media: stkwebcam: fix runtime PM after driver unbind
	tracing/hwlat: Report total time spent in all NMIs during the sample
	tracing/hwlat: Don't ignore outer-loop duration when calculating max_latency
	tracing: Get trace_array reference for available_tracers files
	x86/asm: Fix MWAITX C-state hint value
	xfs: clear sb->s_fs_info on mount failure
	Linux 4.9.197

Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>

Greg Kroah-Hartman   commited 2019-10-17 13:54:42 -07:00
e9766ef8f1
panic: ensure preemption is disabled during panic()
commit 20bb759a66be52cf4a9ddd17fddaf509e11490cd upstream.

Calling 'panic()' on a kernel with CONFIG_PREEMPT=y can leave the
calling CPU in an infinite loop, but with interrupts and preemption
enabled.  From this state, userspace can continue to be scheduled,
despite the system being "dead" as far as the kernel is concerned.

This is easily reproducible on arm64 when booting with "nosmp" on the
command line; a couple of shell scripts print out a periodic "Ping"
message whilst another triggers a crash by writing to
/proc/sysrq-trigger:

  | sysrq: Trigger a crash
  | Kernel panic - not syncing: sysrq triggered crash
  | CPU: 0 PID: 1 Comm: init Not tainted 5.2.15 #1
  | Hardware name: linux,dummy-virt (DT)
  | Call trace:
  |  dump_backtrace+0x0/0x148
  |  show_stack+0x14/0x20
  |  dump_stack+0xa0/0xc4
  |  panic+0x140/0x32c
  |  sysrq_handle_reboot+0x0/0x20
  |  __handle_sysrq+0x124/0x190
  |  write_sysrq_trigger+0x64/0x88
  |  proc_reg_write+0x60/0xa8
  |  __vfs_write+0x18/0x40
  |  vfs_write+0xa4/0x1b8
  |  ksys_write+0x64/0xf0
  |  __arm64_sys_write+0x14/0x20
  |  el0_svc_common.constprop.0+0xb0/0x168
  |  el0_svc_handler+0x28/0x78
  |  el0_svc+0x8/0xc
  | Kernel Offset: disabled
  | CPU features: 0x0002,24002004
  | Memory Limit: none
  | ---[ end Kernel panic - not syncing: sysrq triggered crash ]---
  |  Ping 2!
  |  Ping 1!
  |  Ping 1!
  |  Ping 2!

The issue can also be triggered on x86 kernels if CONFIG_SMP=n,
otherwise local interrupts are disabled in 'smp_send_stop()'.

Disable preemption in 'panic()' before re-enabling interrupts.

Link: http://lkml.kernel.org/r/20191002123538.22609-1-will@kernel.org
Link: https://lore.kernel.org/r/BX1W47JXPMR8.58IYW53H6M5N@dragonstone
Signed-off-by: Will Deacon <will@kernel.org>
Reported-by: Xogium <contact@xogium.me>
Reviewed-by: Kees Cook <keescook@chromium.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Feng Tang <feng.tang@intel.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Will Deacon   authored and   Greg Kroah-Hartman   commited 2019-10-17 13:42:25 -07:00
9489b435dd
Merge android-4.9.166 (0166b9e) into msm-4.9
* refs/heads/tmp-0166b9e:
  Revert "ANDROID: input: keychord: Add keychord driver"
  Revert "ANDROID: input: misc: keychord: move header to uapi"
  Revert "ANDROID: input: misc: keychord: log when keychord triggered"
  Revert "ANDROID: keychord: Fix a slab out-of-bounds read."
  Revert "Use %zu to print resid (size_t)."
  Revert "ANDROID: keychord: Fix races in keychord_write."
  Revert "ANDROID: keychord: Fix for a memory leak in keychord."
  Revert "ANDROID: keychord: Check for write data size"
  ANDROID: drop CONFIG_INPUT_KEYCHORD from cuttlefish and ranchu
  BACKPORT: mm/debug.c: provide useful debugging information for VM_BUG
  UPSTREAM: bug: use %pB in BUG and stack protector failure
  UPSTREAM: x86/alternative: Print unadorned pointers
  UPSTREAM: trace_uprobe: Display correct offset in uprobe_events
  UPSTREAM: usercopy: Remove pointer from overflow report
  UPSTREAM: Do not hash userspace addresses in fault handlers
  UPSTREAM: mm/slab.c: do not hash pointers when debugging slab
  UPSTREAM: kasan: use %px to print addresses instead of %p
  BACKPORT: vsprintf: add printk specifier %px
  BACKPORT: printk: hash addresses printed with %p
  ANDROID: Fix race in crng_reseed()
  UPSTREAM: siphash: implement HalfSipHash1-3 for hash tables
  UPSTREAM: siphash: add cryptographically secure PRF
  BACKPORT: vsprintf: refactor %pK code out of pointer()
  BACKPORT: docs: correct documentation for %pK
  BACKPORT: filemap: add a comment about FAULT_FLAG_RETRY_NOWAIT behavior
  BACKPORT: filemap: drop the mmap_sem for all blocking operations
  BACKPORT: filemap: kill page_cache_read usage in filemap_fault
  ANDROID: binder: remove extra declaration left after backport
  UPSTREAM: net: socket: set sock->sk to NULL after calling proto_ops::release()
  FROMGIT: binder: fix BUG_ON found by selinux-testsuite
  Linux 4.9.166
  ath10k: avoid possible string overflow
  power: supply: charger-manager: Fix incorrect return value
  pwm-backlight: Enable/disable the PWM before/after LCD enable toggle.
  rtc: Fix overflow when converting time64_t to rtc_time
  scsi: ufs: fix wrong command type of UTRD for UFSHCI v2.1
  USB: core: only clean up what we allocated
  lib/int_sqrt: optimize small argument
  serial: sprd: clear timeout interrupt only rather than all interrupts
  arm64: traps: disable irq in die()
  Hang/soft lockup in d_invalidate with simultaneous calls
  serial: sprd: adjust TIMEOUT to a big value
  tcp/dccp: drop SYN packets if accept queue is full
  ALSA: hda - Enforces runtime_resume after S3 and S4 for each codec
  ALSA: hda - Record the current power state before suspend/resume calls
  locking/lockdep: Add debug_locks check in __lock_downgrade()
  Bluetooth: Fix decrementing reference count twice in releasing socket
  media: v4l2-ctrls.c/uvc: zero v4l2_event
  ext4: brelse all indirect buffer in ext4_ind_remove_space()
  ext4: fix data corruption caused by unaligned direct AIO
  ext4: fix NULL pointer dereference while journal is aborted
  objtool: Move objtool_file struct off the stack
  futex: Ensure that futex address is aligned in handle_futex_death()
  MIPS: Fix kernel crash for R6 in jump label branch function
  MIPS: Ensure ELF appended dtb is relocated
  mips: loongson64: lemote-2f: Add IRQF_NO_SUSPEND to "cascade" irqaction.
  udf: Fix crash on IO error during truncate
  libceph: wait for latest osdmap in ceph_monc_blacklist_add()
  iommu/amd: fix sg->dma_address for sg->offset bigger than PAGE_SIZE
  drm/vmwgfx: Don't double-free the mode stored in par->set_mode
  mmc: pxamci: fix enum type confusion
  ANDROID: dm-bow: Fix 32 bit compile errors
  ANDROID: fix 4.9 backport of psi header refactoring
  UPSTREAM: mm: proc: smaps_rollup: fix pss_locked calculation
  UPSTREAM: binder: fix handling of misaligned binder object
  UPSTREAM: binder: fix sparse issue in binder_alloc_selftest.c
  BACKPORT: binder: use userspace pointer as base of buffer space
  UPSTREAM: binder: fix kerneldoc header for struct binder_buffer
  BACKPORT: binder: remove user_buffer_offset
  UPSTREAM: binder: remove kernel vm_area for buffer space
  UPSTREAM: binder: avoid kernel vm_area for buffer fixups
  BACKPORT: binder: add function to copy binder object from buffer
  BACKPORT: binder: add functions to copy to/from binder buffers
  UPSTREAM: binder: create userspace-to-binder-buffer copy function
  ANDROID: Add dm-bow to cuttlefish configuration
  ANDROID: dm-bow: Backport to 4.9
  ANDROID: dm-bow: backport to 4.14
  ANDROID: dm-bow: Add dm-bow feature
  f2fs: set pin_file under CAP_SYS_ADMIN
  f2fs: fix to avoid deadlock in f2fs_read_inline_dir()
  f2fs: fix to adapt small inline xattr space in __find_inline_xattr()
  f2fs: fix to do sanity check with inode.i_inline_xattr_size
  f2fs: give some messages for inline_xattr_size
  f2fs: don't trigger read IO for beyond EOF page
  f2fs: fix to add refcount once page is tagged PG_private
  f2fs: remove wrong comment in f2fs_invalidate_page()
  f2fs: fix to use kvfree instead of kzfree
  f2fs: print more parameters in trace_f2fs_map_blocks
  f2fs: trace f2fs_ioc_shutdown
  f2fs: fix to avoid deadlock of atomic file operations
  f2fs: fix to dirty inode for i_mode recovery
  f2fs: give random value to i_generation
  f2fs: no need to take page lock in readdir
  f2fs: fix to update iostat correctly in IPU path
  f2fs: fix encrypted page memory leak
  f2fs: make fault injection covering __submit_flush_wait()
  f2fs: fix to retry fill_super only if recovery failed
  f2fs: silence VM_WARN_ON_ONCE in mempool_alloc
  f2fs: correct spelling mistake
  f2fs: fix wrong #endif
  f2fs: don't clear CP_QUOTA_NEED_FSCK_FLAG
  f2fs: don't allow negative ->write_io_size_bits
  f2fs: fix to check inline_xattr_size boundary correctly
  Revert "f2fs: fix to avoid deadlock of atomic file operations"
  Revert "f2fs: fix to check inline_xattr_size boundary correctly"
  f2fs: do not use mutex lock in atomic context
  f2fs: fix potential data inconsistence of checkpoint
  f2fs: fix to avoid deadlock of atomic file operations
  f2fs: fix to check inline_xattr_size boundary correctly
  f2fs: jump to label 'free_node_inode' when failing from d_make_root()
  f2fs: fix to document inline_xattr_size option
  f2fs: fix to data block override node segment by mistake
  f2fs: fix typos in code comments
  f2fs: use xattr_prefix to wrap up
  f2fs: sync filesystem after roll-forward recovery
  fs: export evict_inodes
  f2fs: flush quota blocks after turnning it off
  f2fs: avoid null pointer exception in dcc_info
  f2fs: don't wake up too frequently, if there is lots of IOs
  f2fs: try to keep CP_TRIMMED_FLAG after successful umount
  f2fs: add quick mode of checkpoint=disable for QA
  f2fs: run discard jobs when put_super
  f2fs: fix to set sbi dirty correctly
  f2fs: UBSAN: set boolean value iostat_enable correctly
  f2fs: add brackets for macros
  f2fs: check if file namelen exceeds max value
  f2fs: fix to trigger fsck if dirent.name_len is zero
  f2fs: no need to check return value of debugfs_create functions
  f2fs: export FS_NOCOW_FL flag to user
  f2fs: check inject_rate validity during configuring
  f2fs: remove set but not used variable 'err'
  f2fs: fix compile warnings: 'struct *' declared inside parameter list
  f2fs: change error code to -ENOMEM from -EINVAL

Conflicts:
	arch/arm64/kernel/traps.c
	drivers/input/misc/Kconfig
	drivers/scsi/ufs/ufshcd.c
	kernel/sched/core.c

Change-Id: I39b9d8198c85c7651ab76609f545104c71dc38df
Signed-off-by: jianzhou <jianzhou@codeaurora.org>

jianzhou   commited 2019-05-23 14:26:39 +08:00
19d550fc89
UPSTREAM: bug: use %pB in BUG and stack protector failure
The BUG and stack protector reports were still using a raw %p.  This
changes it to %pB for more meaningful output.

Link: http://lkml.kernel.org/r/20180301225704.GA34198@beast
Fixes: ad67b74d2469 ("printk: hash addresses printed with %p")
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Richard Weinberger <richard.weinberger@gmail.com>,
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
(cherry picked from commit 0862ca422b79cb5aa70823ee0f07f6b468f86070)
Signed-off-by: Sandeep Patil <sspatil@android.com>

Bug: 78533979
Test: Build and boot cuttlefish
Change-Id: Id4ff4ef7d236f1d7ce6d61ef071bd0d4414c8dd2

Kees Cook   authored and   Alistair Strachan   commited 2019-03-28 21:13:06 -07:00
96dc04da6c
Merge android-4.9.149 (ed0b11d) into msm-4.9
*  refs/heads/tmp-ed0b11d:
  Linux 4.9.149
  spi: bcm2835: Unbreak the build of esoteric configs
  tpm: tpm_i2c_nuvoton: use correct command duration for TPM 2.x
  rtc: m41t80: Correct alarm month range with RTC reads
  arm64: KVM: Avoid setting the upper 32 bits of VTCR_EL2 to 1
  x86/kvm/vmx: do not use vm-exit instruction length for fast MMIO when running nested
  CIFS: Fix error mapping for SMB2_LOCK command which caused OFD lock problem
  MIPS: OCTEON: mark RGMII interface disabled on OCTEON III
  MIPS: Align kernel load address to 64KB
  MIPS: Ensure pmd_present() returns false after pmd_mknotpresent()
  media: v4l2-tpg: array index could become negative
  media: vivid: free bitmap_cap when updating std/timings/etc.
  serial: uartps: Fix interrupt mask issue to handle the RX interrupts properly
  f2fs: fix validation of the block count in sanity_check_raw_super
  cdc-acm: fix abnormal DATA RX issue for Mediatek Preloader.
  clk: rockchip: fix typo in rk3188 spdif_frac parent
  spi: bcm2835: Avoid finishing transfer prematurely in IRQ mode
  spi: bcm2835: Fix book-keeping of DMA termination
  spi: bcm2835: Fix race on DMA termination
  ext4: force inode writes when nfsd calls commit_metadata()
  ext4: include terminating u32 in size of xattr entries when expanding inodes
  ext4: fix EXT4_IOC_GROUP_ADD ioctl
  ext4: missing unlock/put_page() in ext4_try_to_write_inline_data()
  ext4: fix possible use after free in ext4_quota_enable
  perf pmu: Suppress potential format-truncation warning
  platform-msi: Free descriptors in platform_msi_domain_free()
  KVM: x86: Use jmp to invoke kvm_spurious_fault() from .fixup
  Input: elan_i2c - add ACPI ID for touchpad in ASUS Aspire F5-573G
  qmi_wwan: apply SET_DTR quirk to the SIMCOM shared device ID
  staging: wilc1000: fix missing read_write setting when reading data
  usb: r8a66597: Fix a possible concurrency use-after-free bug in r8a66597_endpoint_disable()
  USB: serial: option: add Fibocom NL678 series
  USB: serial: pl2303: add ids for Hewlett-Packard HP POS pole displays
  ALSA: hda/tegra: clear pending irq handlers
  ALSA: hda: add mute LED support for HP EliteBook 840 G4
  mtd: atmel-quadspi: disallow building on ebsa110
  ALSA: emux: Fix potential Spectre v1 vulnerabilities
  ALSA: pcm: Fix potential Spectre v1 vulnerability
  ALSA: emu10k1: Fix potential Spectre v1 vulnerabilities
  ALSA: rme9652: Fix potential Spectre v1 vulnerability
  ptr_ring: wrap back ->producer in __ptr_ring_swap_queue()
  sock: Make sock->sk_stamp thread-safe
  net/mlx5: Typo fix in del_sw_hw_rule
  net/mlx5e: Remove the false indication of software timestamping support
  gro_cell: add napi_disable in gro_cells_destroy
  tipc: compare remote and local protocols in tipc_udp_enable()
  tipc: use lock_sock() in tipc_sk_reinit()
  xen/netfront: tolerate frags with no data
  VSOCK: Send reset control packet when socket is partially bound
  vhost: make sure used idx is seen before log in vhost_add_used_n()
  tipc: fix a double kfree_skb()
  sctp: initialize sin6_flowinfo for ipv6 addrs in sctp_inet6addr_event
  packet: validate address length if non-zero
  packet: validate address length
  net/wan: fix a double free in x25_asy_open_tty()
  netrom: fix locking in nr_find_socket()
  net: phy: Fix the issue that netif always links up after resuming
  net: ipv4: do not handle duplicate fragments as overlapping
  isdn: fix kernel-infoleak in capi_unlocked_ioctl
  ipv6: tunnels: fix two use-after-free
  ipv6: explicitly initialize udp6_addr in udp_sock_create6()
  ieee802154: lowpan_header_create check must check daddr
  ibmveth: fix DMA unmap error in ibmveth_xmit_start error path
  ax25: fix a use-after-free in ax25_fillin_cb()
  ipv4: Fix potential Spectre v1 vulnerability
  ip6mr: Fix potential Spectre v1 vulnerability
  NFC: nxp-nci: Include unaligned.h instead of access_ok.h
  UPSTREAM: mm: /proc/pid/smaps_rollup: fix NULL pointer deref in smaps_pte_range()
  BACKPORT: fs/proc/task_mmu.c: fix Locked field in /proc/pid/smaps*
  BACKPORT: mm: add /proc/pid/smaps_rollup
  ANDROID: cuttlefish_defconfig: Enable VIRTIO_INPUT
  Linux 4.9.148
  drm/ioctl: Fix Spectre v1 vulnerabilities
  proc/sysctl: don't return ENOMEM on lookup when a table is unregistering
  panic: avoid deadlocks in re-entrant console drivers
  ubifs: Handle re-linking of inodes correctly while recovery
  x86/fpu: Disable bottom halves while loading FPU registers
  x86/mtrr: Don't copy uninitialized gentry fields back to userspace
  Drivers: hv: vmbus: Return -EINVAL for the sys files for unopened channels
  gpio: max7301: fix driver for use with CONFIG_VMAP_STACK
  mmc: omap_hsmmc: fix DMA API warning
  mmc: core: Use a minimum 1600ms timeout when enabling CACHE ctrl
  mmc: core: Allow BKOPS and CACHE ctrl even if no HPI support
  mmc: core: Reset HPI enabled state during re-init and in case of errors
  USB: serial: option: add Telit LN940 series
  USB: serial: option: add Fibocom NL668 series
  USB: serial: option: add Simcom SIM7500/SIM7600 (MBIM mode)
  USB: serial: option: add HP lt4132
  USB: serial: option: add GosunCn ZTE WeLink ME3630
  xhci: Don't prevent USB2 bus suspend in state check intended for USB3 only
  USB: hso: Fix OOB memory access in hso_probe/hso_get_config_data
  ib_srpt: Fix a use-after-free in __srpt_close_all_ch()
  block: fix infinite loop if the device loses discard capability
  block: break discard submissions into the user defined size
  Linux 4.9.147
  rtc: snvs: Add timeouts to avoid kernel lockups
  rtc: snvs: add a missing write sync
  nvmet-rdma: fix response use after free
  i2c: scmi: Fix probe error on devices with an empty SMB0001 ACPI device node
  i2c: axxia: properly handle master timeout
  vhost/vsock: fix reset orphans race with close timeout
  cifs: In Kconfig CONFIG_CIFS_POSIX needs depends on legacy (insecure cifs)
  drm/ast: Fix connector leak during driver unload
  ethernet: fman: fix wrong of_node_put() in probe function
  ARM: 8815/1: V7M: align v7m_dma_inv_range() with v7 counterpart
  ARM: 8814/1: mm: improve/fix ARM v7_dma_inv_range() unaligned address handling
  bpf: check pending signals while verifying programs
  net/mlx4_en: Fix build break when CONFIG_INET is off
  mv88e6060: disable hardware level MAC learning
  libata: whitelist all SAMSUNG MZ7KM* solid-state disks
  Input: omap-keypad - fix keyboard debounce configuration
  clk: mmp: Off by one in mmp_clk_add()
  clk: mvebu: Off by one bugs in cp110_of_clk_get()
  ide: pmac: add of_node_put()
  drivers/tty: add missing of_node_put()
  drivers/sbus/char: add of_node_put()
  sbus: char: add of_node_put()
  SUNRPC: Fix a potential race in xprt_connect()
  nfs: don't dirty kernel pages read by direct-io
  bonding: fix 802.3ad state sent to partner when unbinding slave
  ARC: io.h: Implement reads{x}()/writes{x}()
  drm/msm: Grab a vblank reference when waiting for commit_done
  x86/earlyprintk/efi: Fix infinite loop on some screen widths
  scsi: vmw_pscsi: Rearrange code to avoid multiple calls to free_irq during unload
  scsi: libiscsi: Fix NULL pointer dereference in iscsi_eh_session_reset
  mac80211_hwsim: fix module init error paths for netlink
  locking/qspinlock: Fix build for anonymous union in older GCC compilers
  locking/qspinlock, x86: Provide liveness guarantee
  locking/qspinlock/x86: Increase _Q_PENDING_LOOPS upper bound
  locking/qspinlock: Re-order code
  locking/qspinlock: Kill cmpxchg() loop when claiming lock from head of queue
  locking/qspinlock: Remove duplicate clear_pending() function from PV code
  locking/qspinlock: Remove unbounded cmpxchg() loop from locking slowpath
  locking/qspinlock: Merge 'struct __qspinlock' into 'struct qspinlock'
  locking/qspinlock: Bound spinning on pending->locked transition in slowpath
  locking/qspinlock: Ensure node is initialised before updating prev->next
  locking: Remove smp_read_barrier_depends() from queued_spin_lock_slowpath()
  IB/hfi1: Remove race conditions in user_sdma send path
  mac80211: Fix condition validating WMM IE
  mac80211: don't WARN on bad WMM parameters from buggy APs
  drm/i915/execlists: Apply a full mb before execution for Braswell
  Revert "drm/rockchip: Allow driver to be shutdown on reboot/kexec"
  powerpc/msi: Fix NULL pointer access in teardown code
  tracing: Fix memory leak of instance function hash filters
  tracing: Fix memory leak in set_trigger_filter()
  ARM: mmp/mmp2: fix cpu_is_mmp2() on mmp2-dt
  MMC: OMAP: fix broken MMC on OMAP15XX/OMAP5910/OMAP310
  aio: fix spectre gadget in lookup_ioctx
  pinctrl: sunxi: a83t: Fix IRQ offset typo for PH11
  timer/debug: Change /proc/timer_list from 0444 to 0400
  lib/interval_tree_test.c: allow users to limit scope of endpoint
  lib/rbtree-test: lower default params
  lib/rbtree_test.c: make input module parameters
  lib/interval_tree_test.c: allow full tree search
  lib/interval_tree_test.c: make test options module parameters
  signal: Introduce COMPAT_SIGMINSTKSZ for use in compat_sys_sigaltstack
  ANDROID: Revert fs/squashfs back to linux-4.9.y
  BACKPORT, FROMGIT: dm verity: log the hash algorithm implementation
  BACKPORT, FROMGIT: dm crypt: log the encryption algorithm implementation
  Linux 4.9.146
  staging: speakup: Replace strncpy with memcpy
  pstore: Convert console write to use ->write_buf
  ocfs2: fix potential use after free
  debugobjects: avoid recursive calls with kmemleak
  hfsplus: do not free node before using
  hfs: do not free node before using
  ocfs2: fix deadlock caused by ocfs2_defrag_extent()
  fscache, cachefiles: remove redundant variable 'cache'
  fscache: fix race between enablement and dropping of object
  xen: xlate_mmu: add missing header to fix 'W=1' warning
  drm/ast: fixed reading monitor EDID not stable issue
  net: hisilicon: remove unexpected free_netdev
  ixgbe: recognize 1000BaseLX SFP modules as 1Gbps
  igb: fix uninitialized variables
  cachefiles: Fix page leak in cachefiles_read_backing_file while vmscan is active
  net: thunderx: fix NULL pointer dereference in nic_remove
  x86/kvm/vmx: fix old-style function declaration
  KVM: x86: fix empty-body warnings
  USB: omap_udc: fix USB gadget functionality on Palm Tungsten E
  USB: omap_udc: fix omap_udc_start() on 15xx machines
  USB: omap_udc: fix crashes on probe error and module removal
  USB: omap_udc: use devm_request_irq()
  ipvs: call ip_vs_dst_notifier earlier than ipv6_dev_notf
  bpf: fix check of allowed specifiers in bpf_trace_printk
  exportfs: do not read dentry after free
  ASoC: omap-dmic: Add pm_qos handling to avoid overruns with CPU_IDLE
  ASoC: omap-mcpdm: Add pm_qos handling to avoid under/overruns with CPU_IDLE
  RDMA/mlx5: Fix fence type for IB_WR_LOCAL_INV WR
  Btrfs: send, fix infinite loop due to directory rename dependencies
  objtool: Fix segfault in .cold detection with -ffunction-sections
  objtool: Fix double-free in .cold detection error path
  hwmon: (w83795) temp4_type has writable permission
  ASoC: dapm: Recalculate audio map forcely when card instantiated
  ASoC: omap-abe-twl6040: Fix missing audio card caused by deferred probing
  hwmon: (ina2xx) Fix current value calculation
  s390/cpum_cf: Reject request for sampling in event initialization
  selftests: add script to stress-test nft packet path vs. control plane
  sysv: return 'err' instead of 0 in __sysv_write_inode
  ARM: OMAP1: ams-delta: Fix possible use of uninitialized field
  ARM: dts: logicpd-somlv: Fix interrupt on mmc3_dat1
  ARM: OMAP2+: prm44xx: Fix section annotation on omap44xx_prm_enable_io_wakeup
  neighbour: Avoid writing before skb->head in neigh_hh_output()
  tun: forbid iface creation with rtnl ops
  tcp: fix NULL ref in tail loss probe
  rtnetlink: ndo_dflt_fdb_dump() only work for ARPHRD_ETHER devices
  net: Prevent invalid access to skb->prev in __qdisc_drop_all
  net: phy: don't allow __set_phy_supported to add unsupported modes
  net/mlx4_core: Correctly set PFC param if global pause is turned off.
  net: 8139cp: fix a BUG triggered by changing mtu with network traffic
  ipv6: Check available headroom in ip6_xmit() even without options
  Makefile: Properly resolve conflict from 4.9.145
  ANDROID: cuttlefish_defconfig: Enable CONFIG_CRYPTO_ADIANTUM
  UPSTREAM: dm crypt: don't decrease device limits
  BACKPORT: dm crypt: allow unaligned bv_offset
  BACKPORT: dm crypt: reject sector_size feature if device length is not aligned to it
  BACKPORT: dm crypt: use shifts instead of sector_div
  BACKPORT: dm crypt: optionally support larger encryption sector size
  BACKPORT, FROMGIT: fscrypt: add Adiantum support
  BACKPORT, FROMGIT: crypto: adiantum - add Adiantum support
  FROMGIT: crypto: arm/nhpoly1305 - add NEON-accelerated NHPoly1305
  BACKPORT, FROMGIT: crypto: nhpoly1305 - add NHPoly1305 support
  FROMGIT: crypto: poly1305 - add Poly1305 core API
  FROMGIT: crypto: poly1305 - use structures for key and accumulator
  BACKPORT, FROMGIT: crypto: arm/chacha - add XChaCha12 support
  BACKPORT, FROMGIT: crypto: arm/chacha20 - refactor to allow varying number of rounds
  BACKPORT, FROMGIT: crypto: arm/chacha20 - add XChaCha20 support
  BACKPORT, FROMGIT: crypto: arm/chacha20 - limit the preemption-disabled section
  BACKPORT, FROMGIT: crypto: chacha - add XChaCha12 support
  BACKPORT, FROMGIT: crypto: chacha20-generic - refactor to allow varying number of rounds
  BACKPORT, FROMGIT: crypto: chacha20-generic - add XChaCha20 support
  FROMGIT: crypto: chacha20-generic - add HChaCha20 library function
  FROMGIT: crypto: arm/aes - add some hardening against cache-timing attacks
  UPSTREAM: crypto: arm/aes-cipher - move S-box to .rodata section
  UPSTREAM: crypto: arm/aes - avoid expanded lookup tables in the final round
  UPSTREAM: crypto: arm/aes - avoid reserved 'tt' mnemonic in asm code
  BACKPORT: crypto: arm/aes - replace scalar AES cipher
  UPSTREAM: crypto: poly1305 - use unaligned access macros to output digest
  UPSTREAM: crypto: poly1305 - Use unaligned access where required
  UPSTREAM: crypto: arm/chacha20 - faster 8-bit rotations and other optimizations
  UPSTREAM: crypto: arm/chacha20 - always use vrev for 16-bit rotates
  BACKPORT: crypto: arm/chacha20 - implement NEON version based on SSE3 code
  BACKPORT: crypto: chacha20 - Fix chacha20_block() keystream alignment (again)
  UPSTREAM: crypto: chacha20 - use rol32() macro from bitops.h
  BACKPORT: crypto: chacha20 - Fix keystream alignment for chacha20_block()
  UPSTREAM: crypto: chacha20 - Use unaligned access macros when loading key and IV
  UPSTREAM: crypto: chacha20 - Fix unaligned access when loading constants
  UPSTREAM: crypto: testmgr - fix overlap in chunked tests again
  UPSTREAM: crypto: testmgr - avoid overlap in chunked tests
  ANDROID: cuttlefish_defconfig: Enable VIRT_WIFI
  FROMGIT, BACKPORT: mac80211-next: rtnetlink wifi simulation device
  ANDROID: cuttlefish_defconfig: Enable CONFIG_ARM64_LSE_ATOMICS
  ANDROID: Move from clang r328903 to r346389b.
  ANDROID: arm64 defconfig / build config for cuttlefish

Conflicts:
	drivers/char/random.c
	drivers/md/dm-crypt.c
	drivers/mmc/core/mmc.c
	drivers/net/wireless/Kconfig
	drivers/net/wireless/Makefile
	fs/crypto/fscrypt_private.h
	fs/crypto/keyinfo.c
	include/uapi/linux/fs.h

Change-Id: I3f7617ac7ab346b0650757e25ef3e7daf4d97a1e
Signed-off-by: jianzhou <jianzhou@codeaurora.org>

jianzhou   commited 2019-02-12 11:18:51 +08:00
b62aeea0ec
panic: avoid deadlocks in re-entrant console drivers
commit c7c3f05e341a9a2bd1a92993d4f996cfd6e7348e upstream.

From printk()/serial console point of view panic() is special, because
it may force CPU to re-enter printk() or/and serial console driver.
Therefore, some of serial consoles drivers are re-entrant. E.g. 8250:

serial8250_console_write()
{
	if (port->sysrq)
		locked = 0;
	else if (oops_in_progress)
		locked = spin_trylock_irqsave(&port->lock, flags);
	else
		spin_lock_irqsave(&port->lock, flags);
	...
}

panic() does set oops_in_progress via bust_spinlocks(1), so in theory
we should be able to re-enter serial console driver from panic():

	CPU0
	<NMI>
	uart_console_write()
	serial8250_console_write()		// if (oops_in_progress)
						//    spin_trylock_irqsave()
	call_console_drivers()
	console_unlock()
	console_flush_on_panic()
	bust_spinlocks(1)			// oops_in_progress++
	panic()
	<NMI/>
	spin_lock_irqsave(&port->lock, flags)   // spin_lock_irqsave()
	serial8250_console_write()
	call_console_drivers()
	console_unlock()
	printk()
	...

However, this does not happen and we deadlock in serial console on
port->lock spinlock. And the problem is that console_flush_on_panic()
called after bust_spinlocks(0):

void panic(const char *fmt, ...)
{
	bust_spinlocks(1);
	...
	bust_spinlocks(0);
	console_flush_on_panic();
	...
}

bust_spinlocks(0) decrements oops_in_progress, so oops_in_progress
can go back to zero. Thus even re-entrant console drivers will simply
spin on port->lock spinlock. Given that port->lock may already be
locked either by a stopped CPU, or by the very same CPU we execute
panic() on (for instance, NMI panic() on printing CPU) the system
deadlocks and does not reboot.

Fix this by removing bust_spinlocks(0), so oops_in_progress is always
set in panic() now and, thus, re-entrant console drivers will trylock
the port->lock instead of spinning on it forever, when we call them
from console_flush_on_panic().

Link: http://lkml.kernel.org/r/20181025101036.6823-1-sergey.senozhatsky@gmail.com
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Daniel Wang <wonderfly@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Alan Cox <gnomes@lxorguk.ukuu.org.uk>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: Peter Feiner <pfeiner@google.com>
Cc: linux-serial@vger.kernel.org
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Sergey Senozhatsky   authored and   Greg Kroah-Hartman   commited 2018-12-29 13:40:16 +01:00
6c976b42dc
soc: qcom: Register default dump entries to minidump table
Add below common dump entries to minidump table:
All memory dump table entries, kernel data/bss sections,
percpu static sections, rtb, logbuf, wdogdata, lpm_debug,
stackpointer, and current task struct.
Also add name for memory dump table entries to accommodate
Minidump support.

Change-Id: I45d121bc36b40332cfd0a0f5142572c6ce8f8a26
Signed-off-by: Lingutla Chandrasekhar <clingutla@codeaurora.org>

Lingutla Chandrasekhar   commited 2017-11-27 14:22:11 +05:30
be48b0764d
coresight: abort coresight tracing on kernel crash
Add trace events to control aborting CoreSight trace
dynamically based on module parameter.
Coresight driver will dump any trace present in the current sink
in case we hit a kernel panic, user fault or an undefined instruction.

Change-Id: I668c8cda285250a0b8dcccd2c1d2a8471977ce5c
Signed-off-by: Satyajit Desai <sadesai@codeaurora.org>
Signed-off-by: Rama Aparna Mallavarapu <aparnam@codeaurora.org>

Rama Aparna Mallavarapu   commited 2017-08-30 16:50:09 -07:00
d16ae5ddbc
kernel/panic.c: add missing \n
[ Upstream commit ff7a28a074ccbea999dadbb58c46212cf90984c6 ]

When a system panics, the "Rebooting in X seconds.." message is never
printed because it lacks a new line.  Fix it.

Link: http://lkml.kernel.org/r/20170119114751.2724-1-jslaby@suse.cz
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Jiri Slaby   authored and   Greg Kroah-Hartman   commited 2017-07-05 14:40:24 +02:00
c5c8743642
x86/panic: replace smp_send_stop() with kdump friendly version in panic path
Daniel Walker reported problems which happens when
crash_kexec_post_notifiers kernel option is enabled
(https://lkml.org/lkml/2015/6/24/44).

In that case, smp_send_stop() is called before entering kdump routines
which assume other CPUs are still online.  As the result, for x86, kdump
routines fail to save other CPUs' registers and disable virtualization
extensions.

To fix this problem, call a new kdump friendly function,
crash_smp_send_stop(), instead of the smp_send_stop() when
crash_kexec_post_notifiers is enabled.  crash_smp_send_stop() is a weak
function, and it just call smp_send_stop().  Architecture codes should
override it so that kdump can work appropriately.  This patch only
provides x86-specific version.

For Xen's PV kernel, just keep the current behavior.

NOTES:

- Right solution would be to place crash_smp_send_stop() before
  __crash_kexec() invocation in all cases and remove smp_send_stop(), but
  we can't do that until all architectures implement own
  crash_smp_send_stop()

- crash_smp_send_stop()-like work is still needed by
  machine_crash_shutdown() because crash_kexec() can be called without
  entering panic()

Fixes: f06e5153f4 (kernel/panic.c: add "crash_kexec_post_notifiers" option)
Link: http://lkml.kernel.org/r/20160810080948.11028.15344.stgit@sysi4-13.yrl.intra.hitachi.co.jp
Signed-off-by: Hidehiro Kawai <hidehiro.kawai.ez@hitachi.com>
Reported-by: Daniel Walker <dwalker@fifo99.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Daniel Walker <dwalker@fifo99.com>
Cc: Xunlei Pang <xpang@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: David Vrabel <david.vrabel@citrix.com>
Cc: Toshi Kani <toshi.kani@hpe.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: David Daney <david.daney@cavium.com>
Cc: Aaro Koskinen <aaro.koskinen@iki.fi>
Cc: "Steven J. Hill" <steven.hill@cavium.com>
Cc: Corey Minyard <cminyard@mvista.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Hidehiro Kawai   authored and   Linus Torvalds   commited 2016-10-11 15:06:32 -07:00
0ee59413c9
kexec: use core_param for crash_kexec_post_notifiers boot option
crash_kexec_post_notifiers ia a boot option which controls whether the
1st kernel calls panic notifiers or not before booting the 2nd kernel.
However, there is no need to limit it to being modifiable only at boot
time.  So, use core_param instead of early_param.

Link: http://lkml.kernel.org/r/20160705113327.5864.43139.stgit@softrs
Signed-off-by: Hidehiro Kawai <hidehiro.kawai.ez@hitachi.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Borislav Petkov <bp@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Hidehiro Kawai   authored and   Linus Torvalds   commited 2016-08-02 19:35:29 -04:00
b26e27ddfd
printk/nmi: flush NMI messages on the system panic
In NMI context, printk() messages are stored into per-CPU buffers to
avoid a possible deadlock.  They are normally flushed to the main ring
buffer via an IRQ work.  But the work is never called when the system
calls panic() in the very same NMI handler.

This patch tries to flush NMI buffers before the crash dump is
generated.  In this case it does not risk a double release and bails out
when the logbuf_lock is already taken.  The aim is to get the messages
into the main ring buffer when possible.  It makes them better
accessible in the vmcore.

Then the patch tries to flush the buffers second time when other CPUs
are down.  It might be more aggressive and reset logbuf_lock.  The aim
is to get the messages available for the consequent kmsg_dump() and
console_flush_on_panic() calls.

The patch causes vprintk_emit() to be called even in NMI context again.
But it is done via printk_deferred() so that the console handling is
skipped.  Consoles use internal locks and we could not prevent a
deadlock easily.  They are explicitly called later when the crash dump
is not generated, see console_flush_on_panic().

Signed-off-by: Petr Mladek <pmladek@suse.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Daniel Thompson <daniel.thompson@linaro.org>
Cc: David Miller <davem@davemloft.net>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jiri Kosina <jkosina@suse.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Russell King <rmk+kernel@arm.linux.org.uk>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Petr Mladek   authored and   Linus Torvalds   commited 2016-05-20 17:58:30 -07:00
cf9b1106c8
panic: change nmi_panic from macro to function
Commit 1717f2096b ("panic, x86: Fix re-entrance problem due to panic
on NMI") and commit 58c5661f21 ("panic, x86: Allow CPUs to save
registers even if looping in NMI context") introduced nmi_panic() which
prevents concurrent/recursive execution of panic().  It also saves
registers for the crash dump on x86.

However, there are some cases where NMI handlers still use panic().
This patch set partially replaces them with nmi_panic() in those cases.

Even this patchset is applied, some NMI or similar handlers (e.g.  MCE
handler) continue to use panic().  This is because I can't test them
well and actual problems won't happen.  For example, the possibility
that normal panic and panic on MCE happen simultaneously is very low.

This patch (of 3):

Convert nmi_panic() to a proper function and export it instead of
exporting internal implementation details to modules, for obvious
reasons.

Signed-off-by: Hidehiro Kawai <hidehiro.kawai.ez@hitachi.com>
Acked-by: Borislav Petkov <bp@suse.de>
Acked-by: Michal Nazarewicz <mina86@mina86.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Nicolas Iooss <nicolas.iooss_linux@m4x.org>
Cc: Javi Merino <javi.merino@arm.com>
Cc: Gobinda Charan Maji <gobinda.cemk07@gmail.com>
Cc: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Hidehiro Kawai   authored and   Linus Torvalds   commited 2016-03-22 15:36:02 -07:00
ebc41f20d7
lib/bug.c: use common WARN helper
The traceoff_on_warning option doesn't have any effect on s390, powerpc,
arm64, parisc, and sh because there are two different types of WARN
implementations:

1) The above mentioned architectures treat WARN() as a special case of a
   BUG() exception.  They handle warnings in report_bug() in lib/bug.c.

2) All other architectures just call warn_slowpath_*() directly.  Their
   warnings are handled in warn_slowpath_common() in kernel/panic.c.

Support traceoff_on_warning on all architectures and prevent any future
divergence by using a single common function to emit the warning.

Also remove the '()' from '%pS()', because the parentheses look funky:

  [   45.607629] WARNING: at /root/warn_mod/warn_mod.c:17 .init_dummy+0x20/0x40 [warn_mod]()

Reported-by: Chunyu Hu <chuhu@redhat.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Tested-by: Prarit Bhargava <prarit@redhat.com>
Acked-by: Prarit Bhargava <prarit@redhat.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Josh Poimboeuf   authored and   Linus Torvalds   commited 2016-03-17 15:09:34 -07:00
2553b67a1f
printk: do cond_resched() between lines while outputting to consoles
@console_may_schedule tracks whether console_sem was acquired through
lock or trylock.  If the former, we're inside a sleepable context and
console_conditional_schedule() performs cond_resched().  This allows
console drivers which use console_lock for synchronization to yield
while performing time-consuming operations such as scrolling.

However, the actual console outputting is performed while holding
irq-safe logbuf_lock, so console_unlock() clears @console_may_schedule
before starting outputting lines.  Also, only a few drivers call
console_conditional_schedule() to begin with.  This means that when a
lot of lines need to be output by console_unlock(), for example on a
console registration, the task doing console_unlock() may not yield for
a long time on a non-preemptible kernel.

If this happens with a slow console devices, for example a serial
console, the outputting task may occupy the cpu for a very long time.
Long enough to trigger softlockup and/or RCU stall warnings, which in
turn pile more messages, sometimes enough to trigger the next cycle of
warnings incapacitating the system.

Fix it by making console_unlock() insert cond_resched() between lines if
@console_may_schedule.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Calvin Owens <calvinowens@fb.com>
Acked-by: Jan Kara <jack@suse.com>
Cc: Dave Jones <davej@codemonkey.org.uk>
Cc: Kyle McMartin <kyle@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Tejun Heo   authored and   Linus Torvalds   commited 2016-01-16 11:17:25 -08:00
8d91f8b153
kexec: Fix race between panic() and crash_kexec()
Currently, panic() and crash_kexec() can be called at the same time.
For example (x86 case):

CPU 0:
  oops_end()
    crash_kexec()
      mutex_trylock() // acquired
        nmi_shootdown_cpus() // stop other CPUs

CPU 1:
  panic()
    crash_kexec()
      mutex_trylock() // failed to acquire
    smp_send_stop() // stop other CPUs
    infinite loop

If CPU 1 calls smp_send_stop() before nmi_shootdown_cpus(), kdump
fails.

In another case:

CPU 0:
  oops_end()
    crash_kexec()
      mutex_trylock() // acquired
        <NMI>
        io_check_error()
          panic()
            crash_kexec()
              mutex_trylock() // failed to acquire
            infinite loop

Clearly, this is an undesirable result.

To fix this problem, this patch changes crash_kexec() to exclude others
by using the panic_cpu atomic.

Signed-off-by: Hidehiro Kawai <hidehiro.kawai.ez@hitachi.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: kexec@lists.infradead.org
Cc: linux-doc@vger.kernel.org
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Minfei Huang <mnfhuang@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Seth Jennings <sjenning@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: x86-ml <x86@kernel.org>
Link: http://lkml.kernel.org/r/20151210014630.25437.94161.stgit@softrs
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

Hidehiro Kawai   authored and   Thomas Gleixner   commited 2015-12-19 11:07:01 +01:00
7bbee5ca38
panic, x86: Allow CPUs to save registers even if looping in NMI context
Currently, kdump_nmi_shootdown_cpus(), a subroutine of crash_kexec(),
sends an NMI IPI to CPUs which haven't called panic() to stop them,
save their register information and do some cleanups for crash dumping.
However, if such a CPU is infinitely looping in NMI context, we fail to
save its register information into the crash dump.

For example, this can happen when unknown NMIs are broadcast to all
CPUs as follows:

  CPU 0                             CPU 1
  ===========================       ==========================
  receive an unknown NMI
  unknown_nmi_error()
    panic()                         receive an unknown NMI
      spin_trylock(&panic_lock)     unknown_nmi_error()
      crash_kexec()                   panic()
                                        spin_trylock(&panic_lock)
                                        panic_smp_self_stop()
                                          infinite loop
        kdump_nmi_shootdown_cpus()
          issue NMI IPI -----------> blocked until IRET
                                          infinite loop...

Here, since CPU 1 is in NMI context, the second NMI from CPU 0 is
blocked until CPU 1 executes IRET. However, CPU 1 never executes IRET,
so the NMI is not handled and the callback function to save registers is
never called.

In practice, this can happen on some servers which broadcast NMIs to all
CPUs when the NMI button is pushed.

To save registers in this case, we need to:

  a) Return from NMI handler instead of looping infinitely
  or
  b) Call the callback function directly from the infinite loop

Inherently, a) is risky because NMI is also used to prevent corrupted
data from being propagated to devices.  So, we chose b).

This patch does the following:

1. Move the infinite looping of CPUs which haven't called panic() in NMI
   context (actually done by panic_smp_self_stop()) outside of panic() to
   enable us to refer pt_regs. Please note that panic_smp_self_stop() is
   still used for normal context.

2. Call a callback of kdump_nmi_shootdown_cpus() directly to save
   registers and do some cleanups after setting waiting_for_crash_ipi which
   is used for counting down the number of CPUs which handled the callback

Signed-off-by: Hidehiro Kawai <hidehiro.kawai.ez@hitachi.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Aaron Tomlin <atomlin@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: David Hildenbrand <dahi@linux.vnet.ibm.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Gobinda Charan Maji <gobinda.cemk07@gmail.com>
Cc: HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>
Cc: Hidehiro Kawai <hidehiro.kawai.ez@hitachi.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Javi Merino <javi.merino@arm.com>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: kexec@lists.infradead.org
Cc: linux-doc@vger.kernel.org
Cc: lkml <linux-kernel@vger.kernel.org>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Michal Nazarewicz <mina86@mina86.com>
Cc: Nicolas Iooss <nicolas.iooss_linux@m4x.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Seth Jennings <sjenning@redhat.com>
Cc: Stefan Lippers-Hollmann <s.l-h@gmx.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ulrich Obergfell <uobergfe@redhat.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Link: http://lkml.kernel.org/r/20151210014628.25437.75256.stgit@softrs
[ Cleanup comments, fixup formatting. ]
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

Hidehiro Kawai   authored and   Thomas Gleixner   commited 2015-12-19 11:07:01 +01:00
58c5661f21
panic, x86: Fix re-entrance problem due to panic on NMI
If panic on NMI happens just after panic() on the same CPU, panic() is
recursively called. Kernel stalls, as a result, after failing to acquire
panic_lock.

To avoid this problem, don't call panic() in NMI context if we've
already entered panic().

For that, introduce nmi_panic() macro to reduce code duplication. In
the case of panic on NMI, don't return from NMI handlers if another CPU
already panicked.

Signed-off-by: Hidehiro Kawai <hidehiro.kawai.ez@hitachi.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Aaron Tomlin <atomlin@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: Chris Metcalf <cmetcalf@ezchip.com>
Cc: David Hildenbrand <dahi@linux.vnet.ibm.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Gobinda Charan Maji <gobinda.cemk07@gmail.com>
Cc: HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Javi Merino <javi.merino@arm.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: kexec@lists.infradead.org
Cc: linux-doc@vger.kernel.org
Cc: lkml <linux-kernel@vger.kernel.org>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Michal Nazarewicz <mina86@mina86.com>
Cc: Nicolas Iooss <nicolas.iooss_linux@m4x.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Seth Jennings <sjenning@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ulrich Obergfell <uobergfe@redhat.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Link: http://lkml.kernel.org/r/20151210014626.25437.13302.stgit@softrs
[ Cleanup comments, fixup formatting. ]
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

Hidehiro Kawai   authored and   Thomas Gleixner   commited 2015-12-19 11:07:00 +01:00
1717f2096b
kernel/panic.c: turn off locks debug before releasing console lock
Commit 08d78658f3 ("panic: release stale console lock to always get the
logbuf printed out") introduced an unwanted bad unlock balance report when
panic() is called directly and not from OOPS (e.g.  from out_of_memory()).
The difference is that in case of OOPS we disable locks debug in
oops_enter() and on direct panic call nobody does that.

Fixes: 08d78658f3 ("panic: release stale console lock to always get the logbuf printed out")
Reported-by: kernel test robot <ying.huang@linux.intel.com>
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Baoquan He <bhe@redhat.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Xie XiuQi <xiexiuqi@huawei.com>
Cc: Seth Jennings <sjenning@redhat.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Petr Mladek <pmladek@suse.cz>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Vitaly Kuznetsov   authored and   Linus Torvalds   commited 2015-11-20 16:17:32 -08:00
7625b3a000
panic: release stale console lock to always get the logbuf printed out
In some cases we may end up killing the CPU holding the console lock
while still having valuable data in logbuf. E.g. I'm observing the
following:

- A crash is happening on one CPU and console_unlock() is being called on
  some other.

- console_unlock() tries to print out the buffer before releasing the lock
  and on slow console it takes time.

- in the meanwhile crashing CPU does lots of printk()-s with valuable data
  (which go to the logbuf) and sends IPIs to all other CPUs.

- console_unlock() finishes printing previous chunk and enables interrupts
  before trying to print out the rest, the CPU catches the IPI and never
  releases console lock.

This is not the only possible case: in VT/fb subsystems we have many other
console_lock()/console_unlock() users.  Non-masked interrupts (or
receiving NMI in case of extreme slowness) will have the same result.
Getting the whole console buffer printed out on crash should be top
priority.

[akpm@linux-foundation.org: tweak comment text]
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Baoquan He <bhe@redhat.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Xie XiuQi <xiexiuqi@huawei.com>
Cc: Seth Jennings <sjenning@redhat.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Vitaly Kuznetsov   authored and   Linus Torvalds   commited 2015-11-06 17:50:42 -08:00
08d78658f3
kernel/panic/kexec: fix "crash_kexec_post_notifiers" option issue in oops path
Commit f06e5153f4 ("kernel/panic.c: add "crash_kexec_post_notifiers"
option for kdump after panic_notifers") introduced
"crash_kexec_post_notifiers" kernel boot option, which toggles wheather
panic() calls crash_kexec() before panic_notifiers and dump kmsg or after.

The problem is that the commit overlooks panic_on_oops kernel boot option.
 If it is enabled, crash_kexec() is called directly without going through
panic() in oops path.

To fix this issue, this patch adds a check to "crash_kexec_post_notifiers"
in the condition of kexec_should_crash().

Also, put a comment in kexec_should_crash() to explain not obvious things
on this patch.

Signed-off-by: HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>
Acked-by: Baoquan He <bhe@redhat.com>
Tested-by: Hidehiro Kawai <hidehiro.kawai.ez@hitachi.com>
Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Hidehiro Kawai <hidehiro.kawai.ez@hitachi.com>
Cc: Baoquan He <bhe@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

HATAYAMA Daisuke   authored and   Linus Torvalds   commited 2015-06-30 19:44:57 -07:00
5375b708f2
kernel/panic: call the 2nd crash_kexec() only if crash_kexec_post_notifiers is enabled
For compatibility with the behaviour before the commit f06e5153f4
("kernel/panic.c: add "crash_kexec_post_notifiers" option for kdump after
panic_notifers"), the 2nd crash_kexec() should be called only if
crash_kexec_post_notifiers is enabled.

Note that crash_kexec() returns immediately if kdump crash kernel is not
loaded, so in this case, this patch makes no functionality change, but the
point is to make it explicit, from the caller panic() side, that the 2nd
crash_kexec() does nothing.

Signed-off-by: HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>
Suggested-by: Ingo Molnar <mingo@kernel.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Hidehiro Kawai <hidehiro.kawai.ez@hitachi.com>
Cc: Baoquan He <bhe@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

HATAYAMA Daisuke   authored and   Linus Torvalds   commited 2015-06-30 19:44:57 -07:00
f45d85ff1f
livepatch: kernel: add TAINT_LIVEPATCH
This adds a new taint flag to indicate when the kernel or a kernel
module has been live patched.  This will provide a clean indication in
bug reports that live patching was used.

Additionally, if the crash occurs in a live patched function, the live
patch module will appear beside the patched function in the backtrace.

Signed-off-by: Seth Jennings <sjenning@redhat.com>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Reviewed-by: Petr Mladek <pmladek@suse.cz>
Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

Seth Jennings   authored and   Jiri Kosina   commited 2014-12-22 15:40:48 +01:00
c5f4546593
kernel: add panic_on_warn
There have been several times where I have had to rebuild a kernel to
cause a panic when hitting a WARN() in the code in order to get a crash
dump from a system.  Sometimes this is easy to do, other times (such as
in the case of a remote admin) it is not trivial to send new images to
the user.

A much easier method would be a switch to change the WARN() over to a
panic.  This makes debugging easier in that I can now test the actual
image the WARN() was seen on and I do not have to engage in remote
debugging.

This patch adds a panic_on_warn kernel parameter and
/proc/sys/kernel/panic_on_warn calls panic() in the
warn_slowpath_common() path.  The function will still print out the
location of the warning.

An example of the panic_on_warn output:

The first line below is from the WARN_ON() to output the WARN_ON()'s
location.  After that the panic() output is displayed.

    WARNING: CPU: 30 PID: 11698 at /home/prarit/dummy_module/dummy-module.c:25 init_dummy+0x1f/0x30 [dummy_module]()
    Kernel panic - not syncing: panic_on_warn set ...

    CPU: 30 PID: 11698 Comm: insmod Tainted: G        W  OE  3.17.0+ #57
    Hardware name: Intel Corporation S2600CP/S2600CP, BIOS RMLSDP.86I.00.29.D696.1311111329 11/11/2013
     0000000000000000 000000008e3f87df ffff88080f093c38 ffffffff81665190
     0000000000000000 ffffffff818aea3d ffff88080f093cb8 ffffffff8165e2ec
     ffffffff00000008 ffff88080f093cc8 ffff88080f093c68 000000008e3f87df
    Call Trace:
     [<ffffffff81665190>] dump_stack+0x46/0x58
     [<ffffffff8165e2ec>] panic+0xd0/0x204
     [<ffffffffa038e05f>] ? init_dummy+0x1f/0x30 [dummy_module]
     [<ffffffff81076b90>] warn_slowpath_common+0xd0/0xd0
     [<ffffffffa038e040>] ? dummy_greetings+0x40/0x40 [dummy_module]
     [<ffffffff81076c8a>] warn_slowpath_null+0x1a/0x20
     [<ffffffffa038e05f>] init_dummy+0x1f/0x30 [dummy_module]
     [<ffffffff81002144>] do_one_initcall+0xd4/0x210
     [<ffffffff811b52c2>] ? __vunmap+0xc2/0x110
     [<ffffffff810f8889>] load_module+0x16a9/0x1b30
     [<ffffffff810f3d30>] ? store_uevent+0x70/0x70
     [<ffffffff810f49b9>] ? copy_module_from_fd.isra.44+0x129/0x180
     [<ffffffff810f8ec6>] SyS_finit_module+0xa6/0xd0
     [<ffffffff8166cf29>] system_call_fastpath+0x12/0x17

Successfully tested by me.

hpa said: There is another very valid use for this: many operators would
rather a machine shuts down than being potentially compromised either
functionally or security-wise.

Signed-off-by: Prarit Bhargava <prarit@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Acked-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Prarit Bhargava   authored and   Linus Torvalds   commited 2014-12-10 17:41:10 -08:00
9e3961a097
kernel/panic.c: update comments for print_tainted
Commit 69361eef90 ("panic: add TAINT_SOFTLOCKUP") added the 'L' flag,
but failed to update the comments for print_tainted().  So, update the
comments.

Signed-off-by: Xie XiuQi <xiexiuqi@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Xie XiuQi   authored and   Linus Torvalds   commited 2014-11-13 16:17:06 -08:00
bc53a3f46d
panic: add TAINT_SOFTLOCKUP
This taint flag will be set if the system has ever entered a softlockup
state.  Similar to TAINT_WARN it is useful to know whether or not the
system has been in a softlockup state when debugging.

[akpm@linux-foundation.org: apply the taint before calling panic()]
Signed-off-by: Josh Hunt <johunt@akamai.com>
Cc: Jason Baron <jbaron@akamai.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Josh Hunt   authored and   Linus Torvalds   commited 2014-08-08 15:57:24 -07:00
69361eef90
kernel/panic.c: add "crash_kexec_post_notifiers" option for kdump after panic_notifers
Add a "crash_kexec_post_notifiers" boot option to run kdump after
running panic_notifiers and dump kmsg.  This can help rare situations
where kdump fails because of unstable crashed kernel or hardware failure
(memory corruption on critical data/code), or the 2nd kernel is already
broken by the 1st kernel (it's a broken behavior, but who can guarantee
that the "crashed" kernel works correctly?).

Usage: add "crash_kexec_post_notifiers" to kernel boot option.

Note that this actually increases risks of the failure of kdump.  This
option should be set only if you worry about the rare case of kdump
failure rather than increasing the chance of success.

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Acked-by: Motohiro Kosaki <Motohiro.Kosaki@us.fujitsu.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Yoshihiro YUNOMAE <yoshihiro.yunomae.ez@hitachi.com>
Cc: Satoru MORIYA <satoru.moriya.br@hitachi.com>
Cc: Tomoki Sekiyama <tomoki.sekiyama@hds.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Masami Hiramatsu   authored and   Linus Torvalds   commited 2014-06-06 16:08:12 -07:00
f06e5153f4
kernel/panic.c: display reason at end + pr_emerg
Currently, booting without initrd specified on 80x25 screen gives a call
trace followed by atkbd : Spurious ACK.  Original message ("VFS: Unable
to mount root fs") is not available.  Of course this could happen in
other situations...

This patch displays panic reason after call trace which could help lot
of people even if it's not the very last line on screen.

Also, convert all panic.c printk(KERN_EMERG to pr_emerg(

[akpm@linux-foundation.org: missed a couple of pr_ conversions]
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Fabian Frederick   authored and   Linus Torvalds   commited 2014-04-07 16:36:08 -07:00
d7c0847fe3
Nothing major: the stricter permissions checking for sysfs broke
a staging driver; fix included.  Greg KH said he'd take the patch
 but hadn't as the merge window opened, so it's included here
 to avoid breaking build.
 
 Cheers,
 Rusty.
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Merge tag 'modules-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux

Pull module updates from Rusty Russell:
 "Nothing major: the stricter permissions checking for sysfs broke a
  staging driver; fix included.  Greg KH said he'd take the patch but
  hadn't as the merge window opened, so it's included here to avoid
  breaking build"

* tag 'modules-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux:
  staging: fix up speakup kobject mode
  Use 'E' instead of 'X' for unsigned module taint flag.
  VERIFY_OCTAL_PERMISSIONS: stricter checking for sysfs perms.
  kallsyms: fix percpu vars on x86-64 with relocation.
  kallsyms: generalize address range checking
  module: LLVMLinux: Remove unused function warning from __param_check macro
  Fix: module signature vs tracepoints: add new TAINT_UNSIGNED_MODULE
  module: remove MODULE_GENERIC_TABLE
  module: allow multiple calls to MODULE_DEVICE_TABLE() per module
  module: use pr_cont

Linus Torvalds   commited 2014-04-06 09:38:07 -07:00
6f4c98e1c2
Merge branch 'x86-asmlinkage-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 LTO changes from Peter Anvin:
 "More infrastructure work in preparation for link-time optimization
  (LTO).  Most of these changes is to make sure symbols accessed from
  assembly code are properly marked as visible so the linker doesn't
  remove them.

  My understanding is that the changes to support LTO are still not
  upstream in binutils, but are on the way there.  This patchset should
  conclude the x86-specific changes, and remaining patches to actually
  enable LTO will be fed through the Kbuild tree (other than keeping up
  with changes to the x86 code base, of course), although not
  necessarily in this merge window"

* 'x86-asmlinkage-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (25 commits)
  Kbuild, lto: Handle basic LTO in modpost
  Kbuild, lto: Disable LTO for asm-offsets.c
  Kbuild, lto: Add a gcc-ld script to let run gcc as ld
  Kbuild, lto: add ld-version and ld-ifversion macros
  Kbuild, lto: Drop .number postfixes in modpost
  Kbuild, lto, workaround: Don't warn for initcall_reference in modpost
  lto: Disable LTO for sys_ni
  lto: Handle LTO common symbols in module loader
  lto, workaround: Add workaround for initcall reordering
  lto: Make asmlinkage __visible
  x86, lto: Disable LTO for the x86 VDSO
  initconst, x86: Fix initconst mistake in ts5500 code
  initconst: Fix initconst mistake in dcdbas
  asmlinkage: Make trace_hardirqs_on/off_caller visible
  asmlinkage, x86: Fix 32bit memcpy for LTO
  asmlinkage Make __stack_chk_failed and memcmp visible
  asmlinkage: Mark rwsem functions that can be called from assembler asmlinkage
  asmlinkage: Make main_extable_sort_needed visible
  asmlinkage, mutex: Mark __visible
  asmlinkage: Make trace_hardirq visible
  ...

Linus Torvalds   commited 2014-03-31 14:13:25 -07:00
176ab02d49
Use 'E' instead of 'X' for unsigned module taint flag.
Takashi Iwai <tiwai@suse.de> says:
> The letter 'X' has been already used for SUSE kernels for very long
> time, to indicate the external supported modules.  Can the new flag be
> changed to another letter for avoiding conflict...?
> (BTW, we also use 'N' for "no support", too.)

Note: this code should be cleaned up, so we don't have such maps in
three places!

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

Rusty Russell   commited 2014-03-31 14:52:43 +10:30
57673c2b0b
Rename TAINT_UNSAFE_SMP to TAINT_CPU_OUT_OF_SPEC
Rename TAINT_UNSAFE_SMP to TAINT_CPU_OUT_OF_SPEC, so we can repurpose
the flag to encompass a wider range of pushing the CPU beyond its
warrany.

Signed-off-by: Dave Jones <davej@fedoraproject.org>
Link: http://lkml.kernel.org/r/20140226154949.GA770@redhat.com
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

Dave Jones   authored and   H. Peter Anvin   commited 2014-03-20 16:28:09 -07:00
8c90487cdc
Fix: module signature vs tracepoints: add new TAINT_UNSIGNED_MODULE
Users have reported being unable to trace non-signed modules loaded
within a kernel supporting module signature.

This is caused by tracepoint.c:tracepoint_module_coming() refusing to
take into account tracepoints sitting within force-loaded modules
(TAINT_FORCED_MODULE). The reason for this check, in the first place, is
that a force-loaded module may have a struct module incompatible with
the layout expected by the kernel, and can thus cause a kernel crash
upon forced load of that module on a kernel with CONFIG_TRACEPOINTS=y.

Tracepoints, however, specifically accept TAINT_OOT_MODULE and
TAINT_CRAP, since those modules do not lead to the "very likely system
crash" issue cited above for force-loaded modules.

With kernels having CONFIG_MODULE_SIG=y (signed modules), a non-signed
module is tainted re-using the TAINT_FORCED_MODULE taint flag.
Unfortunately, this means that Tracepoints treat that module as a
force-loaded module, and thus silently refuse to consider any tracepoint
within this module.

Since an unsigned module does not fit within the "very likely system
crash" category of tainting, add a new TAINT_UNSIGNED_MODULE taint flag
to specifically address this taint behavior, and accept those modules
within Tracepoints. We use the letter 'X' as a taint flag character for
a module being loaded that doesn't know how to sign its name (proposed
by Steven Rostedt).

Also add the missing 'O' entry to trace event show_module_flags() list
for the sake of completeness.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
NAKed-by: Ingo Molnar <mingo@redhat.com>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: David Howells <dhowells@redhat.com>
CC: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

Mathieu Desnoyers   authored and   Rusty Russell   commited 2014-03-13 12:11:51 +10:30
66cc69e34e
asmlinkage Make __stack_chk_failed and memcmp visible
In LTO symbols implicitely referenced by the compiler need
to be visible. Earlier these symbols were visible implicitely
from being exported, but we disabled implicit visibility fo
 EXPORTs when modules are disabled to improve code size. So
now these symbols have to be marked visible explicitely.

Do this for __stack_chk_fail (with stack protector)
and memcmp.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Link: http://lkml.kernel.org/r/1391845930-28580-10-git-send-email-ak@linux.intel.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

Andi Kleen   authored and   H. Peter Anvin   commited 2014-02-13 18:13:43 -08:00
a7330c997d
panic: Make panic_timeout configurable
The panic_timeout value can be set via the command line option
'panic=x', or via /proc/sys/kernel/panic, however that is not
sufficient when the panic occurs before we are able to set up
these values. Thus, add a CONFIG_PANIC_TIMEOUT so that we can
set the desired value from the .config.

The default panic_timeout value continues to be 0 - wait
forever. Also adds set_arch_panic_timeout(new_timeout,
arch_default_timeout), which is intended to be used by arches in
arch_setup(). The idea being that the new_timeout is only set if
the user hasn't changed from the arch_default_timeout.

Signed-off-by: Jason Baron <jbaron@akamai.com>
Cc: benh@kernel.crashing.org
Cc: paulus@samba.org
Cc: ralf@linux-mips.org
Cc: mpe@ellerman.id.au
Cc: felipe.contreras@gmail.com
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1a1674daec27c534df409697025ac568ebcee91e.1385418410.git.jbaron@akamai.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

Jason Baron   authored and   Ingo Molnar   commited 2013-11-26 12:12:26 +01:00
5800dc3cff
kernel/panic.c: reduce 1 byte usage for print tainted buffer
sizeof("Tainted: ") already counts '\0', and after first sprintf(), 's'
will start from the current string end (its' value is '\0').

So need not add additional 1 byte for maximized usage of 'buf' in
print_tainted().

Signed-off-by: Chen Gang <gang.chen@asianux.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Chen Gang   authored and   Linus Torvalds   commited 2013-11-13 12:09:35 +09:00
0128476471
panic: call panic handlers before kmsg_dump
Since the panic handlers may produce additional information (via printk)
for the kernel log, it should be reported as part of the panic output
saved by kmsg_dump().  Without this re-ordering, nothing that adds
information to a panic will show up in pstore's view when kmsg_dump runs,
and is therefore not visible to crash reporting tools that examine pstore
output.

Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: Anton Vorontsov <anton@enomsg.org>
Cc: Colin Cross <ccross@android.com>
Acked-by: Tony Luck <tony.luck@intel.com>
Cc: Stephen Boyd <sboyd@codeaurora.org>
Cc: Vikram Mulukutla <markivx@codeaurora.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Kees Cook   authored and   Linus Torvalds   commited 2013-09-11 15:59:30 -07:00
6723734cdf
The majority of the changes here are cleanups for the large changes that
were added to 3.10, which includes several bug fixes that have been
 marked for stable.
 
 As for new features, there were a few, but nothing to write to LWN about.
 These include:
 
 New function trigger called "dump" and "cpudump" that will cause
 ftrace to dump its buffer to the console when the function is called.
 The difference between "dump" and "cpudump" is that "dump" will dump
 the entire contents of the ftrace buffer, where as "cpudump" will only
 dump the contents of the ftrace buffer for the CPU that called the function.
 
 Another small enhancement is a new sysctl switch called "traceoff_on_warning"
 which, when enabled, will disable tracing if any WARN_ON() is triggered.
 This is useful if you want to debug what caused a warning and do not
 want to risk losing your trace data by the ring buffer overwriting the
 data before you can disable it. There's also a kernel command line
 option that will make this enabled at boot up called the same thing.
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Merge tag 'trace-3.11' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull tracing changes from Steven Rostedt:
 "The majority of the changes here are cleanups for the large changes
  that were added to 3.10, which includes several bug fixes that have
  been marked for stable.

  As for new features, there were a few, but nothing to write to LWN
  about.  These include:

  New function trigger called "dump" and "cpudump" that will cause
  ftrace to dump its buffer to the console when the function is called.
  The difference between "dump" and "cpudump" is that "dump" will dump
  the entire contents of the ftrace buffer, where as "cpudump" will only
  dump the contents of the ftrace buffer for the CPU that called the
  function.

  Another small enhancement is a new sysctl switch called
  "traceoff_on_warning" which, when enabled, will disable tracing if any
  WARN_ON() is triggered.  This is useful if you want to debug what
  caused a warning and do not want to risk losing your trace data by the
  ring buffer overwriting the data before you can disable it.  There's
  also a kernel command line option that will make this enabled at boot
  up called the same thing"

* tag 'trace-3.11' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (34 commits)
  tracing: Make tracing_open_generic_{tr,tc}() static
  tracing: Remove ftrace() function
  tracing: Remove TRACE_EVENT_TYPE enum definition
  tracing: Make tracer_tracing_{off,on,is_on}() static
  tracing: Fix irqs-off tag display in syscall tracing
  uprobes: Fix return value in error handling path
  tracing: Fix race between deleting buffer and setting events
  tracing: Add trace_array_get/put() to event handling
  tracing: Get trace_array ref counts when accessing trace files
  tracing: Add trace_array_get/put() to handle instance refs better
  tracing: Protect ftrace_trace_arrays list in trace_events.c
  tracing: Make trace_marker use the correct per-instance buffer
  ftrace: Do not run selftest if command line parameter is set
  tracing/kprobes: Don't pass addr=ip to perf_trace_buf_submit()
  tracing: Use flag buffer_disabled for irqsoff tracer
  tracing/kprobes: Turn trace_probe->files into list_head
  tracing: Fix disabling of soft disable
  tracing: Add missing syscall_metadata comment
  tracing: Simplify code for showing of soft disabled flag
  tracing/kprobes: Kill probe_enable_lock
  ...

Linus Torvalds   commited 2013-07-11 09:02:09 -07:00
c72bb31691
panic: add cpu/pid to warn_slowpath_common in WARNING printk()s
Add the cpu/pid that called WARN() so that the stack traces can be
matched up with the WARNING messages.

[akpm@linux-foundation.org: remove stray quote]
Signed-off-by: Alex Thorlton <athorlton@sgi.com>
Reviewed-by: Robin Holt <holt@sgi.com>
Cc: Stephen Boyd <sboyd@codeaurora.org>
Cc: Vikram Mulukutla <markivx@codeaurora.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Alex Thorlton   authored and   Linus Torvalds   commited 2013-07-09 10:33:25 -07:00
dcb6b45254
tracing: Disable tracing on warning
Add a traceoff_on_warning option in both the kernel command line as well
as a sysctl option. When set, any WARN*() function that is hit will cause
the tracing_on variable to be cleared, which disables writing to the
ring buffer.

This is useful especially when tracing a bug with function tracing. When
a warning is hit, the print caused by the warning can flood the trace with
the functions that producing the output for the warning. This can make the
resulting trace useless by either hiding where the bug happened, or worse,
by overflowing the buffer and losing the trace of the bug totally.

Acked-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

Steven Rostedt (Red Hat)   authored and   Steven Rostedt   commited 2013-06-19 23:32:07 -04:00
de7edd3145
dump_stack: implement arch-specific hardware description in task dumps
x86 and ia64 can acquire extra hardware identification information
from DMI and print it along with task dumps; however, the usage isn't
consistent.

* x86 show_regs() collects vendor, product and board strings and print
  them out with PID, comm and utsname.  Some of the information is
  printed again later in the same dump.

* warn_slowpath_common() explicitly accesses the DMI board and prints
  it out with "Hardware name:" label.  This applies to both x86 and
  ia64 but is irrelevant on all other archs.

* ia64 doesn't show DMI information on other non-WARN dumps.

This patch introduces arch-specific hardware description used by
dump_stack().  It can be set by calling dump_stack_set_arch_desc()
during boot and, if exists, printed out in a separate line with
"Hardware name:" label.

dmi_set_dump_stack_arch_desc() is added which sets arch-specific
description from DMI data.  It uses dmi_ids_string[] which is set from
dmi_present() used for DMI debug message.  It is superset of the
information x86 show_regs() is using.  The function is called from x86
and ia64 boot code right after dmi_scan_machine().

This makes the explicit DMI handling in warn_slowpath_common()
unnecessary.  Removed.

show_regs() isn't yet converted to use generic debug information
printing and this patch doesn't remove the duplicate DMI handling in
x86 show_regs().  The next patch will unify show_regs() handling and
remove the duplication.

An example WARN dump follows.

 WARNING: at kernel/workqueue.c:4841 init_workqueues+0x35/0x505()
 Modules linked in:
 CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.9.0-rc1-work+ #3
 Hardware name: empty empty/S3992, BIOS 080011  10/26/2007
  0000000000000009 ffff88007c861e08 ffffffff81c614dc ffff88007c861e48
  ffffffff8108f500 ffffffff82228240 0000000000000040 ffffffff8234a08e
  0000000000000000 0000000000000000 0000000000000000 ffff88007c861e58
 Call Trace:
  [<ffffffff81c614dc>] dump_stack+0x19/0x1b
  [<ffffffff8108f500>] warn_slowpath_common+0x70/0xa0
  [<ffffffff8108f54a>] warn_slowpath_null+0x1a/0x20
  [<ffffffff8234a0c3>] init_workqueues+0x35/0x505
  ...

v2: Use the same string as the debug message from dmi_present() which
    also contains BIOS information.  Move hardware name into its own
    line as warn_slowpath_common() did.  This change was suggested by
    Bjorn Helgaas.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Fengguang Wu <fengguang.wu@intel.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Jesper Nilsson <jesper.nilsson@axis.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Mike Frysinger <vapier@gentoo.org>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Tejun Heo   authored and   Linus Torvalds   commited 2013-04-30 17:04:02 -07:00
98e5e1bf72
taint: add explicit flag to show whether lock dep is still OK.
Fix up all callers as they were before, with make one change: an
unsigned module taints the kernel, but doesn't turn off lockdep.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

Rusty Russell   commited 2013-01-21 17:17:57 +10:30
373d4d0997
panic: fix a possible deadlock in panic()
panic_lock is meant to ensure that panic processing takes place only on
one cpu; if any of the other cpus encounter a panic, they will spin
waiting to be shut down.

However, this causes a regression in this scenario:

1. Cpu 0 encounters a panic and acquires the panic_lock
   and proceeds with the panic processing.
2. There is an interrupt on cpu 0 that also encounters
   an error condition and invokes panic.
3. This second invocation fails to acquire the panic_lock
   and enters the infinite while loop in panic_smp_self_stop.

Thus all panic processing is stopped, and the cpu is stuck for eternity
in the while(1) inside panic_smp_self_stop.

To address this, disable local interrupts with local_irq_disable before
acquiring the panic_lock.  This will prevent interrupt handlers from
executing during the panic processing, thus avoiding this particular
problem.

Signed-off-by: Vikram Mulukutla <markivx@codeaurora.org>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Cc: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Vikram Mulukutla   authored and   Linus Torvalds   commited 2012-07-30 17:25:13 -07:00
190320c3b6
kdump: Execute kmsg_dump(KMSG_DUMP_PANIC) after smp_send_stop()
This patch moves kmsg_dump(KMSG_DUMP_PANIC) below smp_send_stop(),
to serialize the crash-logging process via smp_send_stop() and to
thus retrieve a more stable crash image of all CPUs stopped.

Signed-off-by: Seiji Aguchi <seiji.aguchi@hds.com>
Acked-by: Don Zickus <dzickus@redhat.com>
Cc: dle-develop@lists.sourceforge.net <dle-develop@lists.sourceforge.net>
Cc: Satoru Moriya <satoru.moriya@hds.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: a.p.zijlstra@chello.nl <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/5C4C569E8A4B9B42A84A977CF070A35B2E4D7A5CE2@USINDEVS01.corp.hds.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

Seiji Aguchi   authored and   Ingo Molnar   commited 2012-05-18 14:02:10 +02:00
62be73eafa
panic: Make panic_on_oops configurable
Several distros set this by default by patching panic_on_oops.
It seems to fit with the BOOTPARAM_{HARD,SOFT}_PANIC options
though, so let's add a Kconfig entry and reduce some more
upstream delta.

Signed-off-by: Kyle McMartin <kyle@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20120411121529.GH26688@redacted.bos.redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

Kyle McMartin   authored and   Ingo Molnar   commited 2012-05-07 14:45:29 +02:00
2a01bb3885
panic: fix stack dump print on direct call to panic()
Commit 6e6f0a1f0f ("panic: don't print redundant backtraces on oops")
causes a regression where no stack trace will be printed at all for the
case where kernel code calls panic() directly while not processing an
oops, and of course there are 100's of instances of this type of call.

The original commit executed the check (!oops_in_progress), but this will
always be false because just before the dump_stack() there is a call to
bust_spinlocks(1), which does the following:

  void __attribute__((weak)) bust_spinlocks(int yes)
  {
	if (yes) {
		++oops_in_progress;

The proper way to resolve the problem that original commit tried to
solve is to avoid printing a stack dump from panic() when the either of
the following conditions is true:

  1) TAINT_DIE has been set (this is done by oops_end())
     This indicates and oops has already been printed.
  2) oops_in_progress > 1
     This guards against the rare case where panic() is invoked
     a second time, or in between oops_begin() and oops_end()

Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: <stable@vger.kernel.org>	[3.3+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Jason Wessel   authored and   Linus Torvalds   commited 2012-04-12 13:12:12 -07:00
026ee1f66a
panic: don't print redundant backtraces on oops
When an oops causes a panic and panic prints another backtrace it's pretty
common to have the original oops data be scrolled away on a 80x50 screen.

The second backtrace is quite redundant and not needed anyways.

So don't print the panic backtrace when oops_in_progress is true.

[akpm@linux-foundation.org: add comment]
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Cc: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Andi Kleen   authored and   Linus Torvalds   commited 2012-01-12 20:13:11 -08:00
6e6f0a1f0f
kdump: fix crash_kexec()/smp_send_stop() race in panic()
When two CPUs call panic at the same time there is a possible race
condition that can stop kdump.  The first CPU calls crash_kexec() and the
second CPU calls smp_send_stop() in panic() before crash_kexec() finished
on the first CPU.  So the second CPU stops the first CPU and therefore
kdump fails:

1st CPU:
  panic()->crash_kexec()->mutex_trylock(&kexec_mutex)-> do kdump

2nd CPU:
  panic()->crash_kexec()->kexec_mutex already held by 1st CPU
       ->smp_send_stop()-> stop 1st CPU (stop kdump)

This patch fixes the problem by introducing a spinlock in panic that
allows only one CPU to process crash_kexec() and the subsequent panic
code.

All other CPUs call the weak function panic_smp_self_stop() that stops the
CPU itself.  This function can be overloaded by architecture code.  For
example "tile" can use their lower-power "nap" instruction for that.

Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Acked-by: Chris Metcalf <cmetcalf@tilera.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Michael Holzheu   authored and   Linus Torvalds   commited 2012-01-12 20:13:11 -08:00
93e13a360b