Mark Rutland
31ad104de6
kcov: ensure irq code sees a valid area ...
[ Upstream commit c9484b986ef03492357fddd50afbdd02929cfa72 ]
Patch series "kcov: fix unexpected faults".
These patches fix a few issues where KCOV code could trigger recursive
faults, discovered while debugging a patch enabling KCOV for arch/arm:
* On CONFIG_PREEMPT kernels, there's a small race window where
__sanitizer_cov_trace_pc() can see a bogus kcov_area.
* Lazy faulting of the vmalloc area can cause mutual recursion between
fault handling code and __sanitizer_cov_trace_pc().
* During the context switch, switching the mm can cause the kcov_area to
be transiently unmapped.
These are prerequisites for enabling KCOV on arm, but the issues
themsevles are generic -- we just happen to avoid them by chance rather
than design on x86-64 and arm64.
This patch (of 3):
For kernels built with CONFIG_PREEMPT, some C code may execute before or
after the interrupt handler, while the hardirq count is zero. In these
cases, in_task() can return true.
A task can be interrupted in the middle of a KCOV_DISABLE ioctl while it
resets the task's kcov data via kcov_task_init(). Instrumented code
executed during this period will call __sanitizer_cov_trace_pc(), and as
in_task() returns true, will inspect t->kcov_mode before trying to write
to t->kcov_area.
In kcov_init_task() we update t->kcov_{mode,area,size} with plain stores,
which may be re-ordered, torn, etc. Thus __sanitizer_cov_trace_pc() may
see bogus values for any of these fields, and may attempt to write to
memory which is not mapped.
Let's avoid this by using WRITE_ONCE() to set t->kcov_mode, with a
barrier() to ensure this is ordered before we clear t->kov_{area,size}.
This ensures that any code execute while kcov_init_task() is preempted
will either see valid values for t->kcov_{area,size}, or will see that
t->kcov_mode is KCOV_MODE_DISABLED, and bail out without touching
t->kcov_area.
Link: http://lkml.kernel.org/r/20180504135535.53744-2-mark.rutland@arm.com
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
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@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-08-03 07:55:12 +02:00
bpf: map_get_next_key to return first key on NULL
2018-05-09 09:50:19 +02:00
config: android: enable CONFIG_SECCOMP
2016-10-11 15:06:32 -07:00
kdb: make "mdr" command repeat
2018-05-30 07:50:51 +02:00
perf/core: Fix perf_output_read_group()
2018-05-30 07:50:46 +02:00
gcov: support GCC 7.1
2017-09-02 07:07:53 +02:00
genirq: Use cpumask_available() for check of cpumask variable
2018-04-08 12:12:44 +02:00
livepatch/module: make TAINT_LIVEPATCH module-specific
2016-08-26 14:42:08 +02:00
locking/qspinlock: Ensure node->count is updated before initialising node
2018-05-30 07:50:26 +02:00
PM / hibernate: Fix oops at snapshot_write()
2018-07-17 11:37:54 +02:00
printk: fix possible reuse of va_list variable
2018-07-03 11:23:10 +02:00
rcu: Call touch_nmi_watchdog() while printing stall warnings
2018-05-30 07:50:50 +02:00
sched/rt: Fix rq->clock_update_flags < RQCF_ACT_SKIP warning
2018-05-30 07:50:41 +02:00
time: Make sure jiffies_to_msecs() preserves non-zero time periods
2018-07-03 11:23:11 +02:00
tracing: Quiet gcc warning about maybe unused link variable
2018-08-03 07:55:12 +02:00
kernel/acct.c: fix the acct->needcheck check in check_free_space()
2018-01-10 09:29:51 +01:00
kernel/async.c: revert "async: simplify lowest_in_progress()"
2018-02-17 13:21:18 +01:00
audit: return on memory error to avoid null pointer dereference
2018-05-30 07:50:49 +02:00
Merge branch 'stable-4.8' of git://git.infradead.org/users/pcmoore/audit
2016-07-29 17:54:17 -07:00
audit: Fix use after free in audit_remove_watch_rule()
2017-08-24 17:12:18 -07:00
audit: add fields to exclude filter by reusing user filter
2016-06-27 11:01:00 -04:00
Merge branch 'stable-4.9' of git://git.infradead.org/users/pcmoore/audit
2016-10-04 14:21:41 -07:00
ptrace: Capture the ptracer's creds not PT_PTRACE_CAP
2017-01-06 10:40:13 +01:00
cgroup: fix error return value from cgroup_subtree_control()
2017-08-11 08:49:28 -07:00
cgroup/pids: remove spurious suspicious RCU usage warning
2017-03-26 13:05:58 +02:00
cpuhotplug: Link lock stacks for hotplug callbacks
2018-04-13 19:48:07 +02:00
sched/cpuset/pm: Fix cpuset vs. suspend-resume bugs
2017-10-12 11:51:25 +02:00
cred: Reject inodes with invalid ids in set_create_file_as()
2016-06-30 18:05:09 -05:00
kernel/exit.c: avoid undefined behaviour when calling wait4()
2018-05-19 10:27:01 +02:00
kernel/extable.c: mark core_kernel_text notrace
2017-07-21 07:42:21 +02:00
kaiser: stack map PAGE_SIZE at THREAD_SIZE-PAGE_SIZE
2018-01-05 15:46:32 +01:00
freezer, oom: check TIF_MEMDIE on the correct task
2016-07-28 16:07:41 -07:00
futex: futex_wake_op, fix sign_extend32 sign bits
2018-05-19 10:27:00 +02:00
kernel: make groups_sort calling a responsibility group_info allocators
2018-01-10 09:29:52 +01:00
hung_task: allow hung_task_panic when hung_task_warnings is 0
2016-10-11 15:06:33 -07:00
jump_label: Invoke jump_label_test() via early_initcall()
2017-12-14 09:28:24 +01:00
kcov: ensure irq code sees a valid area
2018-08-03 07:55:12 +02:00
kexec: allow architectures to override boot mapping
2016-08-02 19:35:27 -04:00
objtool, x86: Add several functions and files to the objtool whitelist
2018-06-05 10:28:57 +02:00
kexec: fix double-free when failing to relocate the purgatory
2016-09-01 17:52:01 -07:00
kprobes/x86: Fix to set RWX bits correctly before releasing trampoline
2018-04-08 12:12:43 +02:00
kexec: add a kexec_crash_loaded() function
2016-08-02 19:35:30 -04:00
kthread, tracing: Don't expose half-written comm when creating kthreads
2018-08-03 07:55:12 +02:00
kernel/watchdog.c: move hardlockup detector to separate file
2017-06-17 06:41:57 +02:00
Fix: Disable sys_membarrier when nohz_full is enabled
2017-03-12 06:41:45 +01:00
mm: Fix devm_memremap_pages() collision handling
2018-02-28 10:18:34 +01:00
module: extend 'rodata=off' boot cmdline parameter to module mappings
2018-04-08 12:12:52 +02:00
padata: free correct variable
2017-05-20 14:28:40 +02:00
kernel/panic.c: add missing \n
2017-07-05 14:40:24 +02:00
pidns: disable pid allocation if pid_ns_prepare_proc() is failed in alloc_pid()
2018-04-13 19:47:53 +02:00
pid_ns: Sleep in TASK_INTERRUPTIBLE in zap_pid_ns_processes
2017-05-25 15:44:38 +02:00
profile: Convert to hotplug state machine
2016-07-15 10:41:42 +02:00
ptrace: Properly initialize ptracer_cred on fork
2017-06-14 15:05:54 +02:00
kernel/relay.c: limit kmalloc size to KMALLOC_MAX_SIZE
2018-05-30 07:50:29 +02:00
resource: fix integer overflow at reallocation
2018-04-24 09:34:09 +02:00
seccomp: Move speculation migitation control to arch code
2018-05-22 16:58:02 +02:00
kernel/signal.c: avoid undefined behaviour in kill_something_info
2018-05-30 07:50:18 +02:00
smp: Allocate smp_call_on_cpu() workqueue on stack too
2016-09-22 14:49:10 +02:00
kthread/smpboot: do not park in kthread_create_on_cpu()
2016-10-11 15:06:33 -07:00
softirq: Display IRQ_POLL for irq-poll statistics
2016-10-21 15:45:47 -06:00
stacktrace, lockdep: Fix address, newline ugliness
2017-02-14 15:25:42 -08:00
Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2016-10-03 13:39:00 -07:00
kernel/sys.c: fix potential Spectre v1 issue
2018-05-30 07:50:18 +02:00
x86/pkeys: Fix pkeys build breakage for some non-x86 arches
2016-09-13 14:41:36 +02:00
timer/sysclt: Restrict timer migration sysctl values to 0 and 1
2017-10-05 09:44:04 +02:00
kernel/sysctl_binary.c: use generic UUID library
2016-05-20 17:58:30 -07:00
task_work: use READ_ONCE/lockless_dereference, avoid pi_lock if !task_works
2016-08-02 19:35:02 -04:00
taskstats: fix the length of cgroupstats_cmd_get_policy
2016-11-03 16:55:58 -04:00
torture: Convert torture_shutdown() to hrtimer
2016-08-22 10:01:49 -07:00
tracepoint: Do not warn on ENOMEM
2018-05-09 09:50:20 +02:00
kernel/ucount.c: mark user_header with kmemleak_ignore()
2017-06-17 06:41:51 +02:00
kernel: make groups_sort calling a responsibility group_info allocators
2018-01-10 09:29:52 +01:00
smp: Add function to execute a function synchronously on a CPU
2016-09-05 13:52:39 +02:00
Merge branch 'nsfs-ioctls' into HEAD
2016-09-22 20:00:36 -05:00
Merge branch 'nsfs-ioctls' into HEAD
2016-09-22 20:00:36 -05:00
kernel/watchdog: prevent false hardlockup on overloaded system
2017-06-17 06:41:57 +02:00
kernel/watchdog: prevent false hardlockup on overloaded system
2017-06-17 06:41:57 +02:00
workqueue: use put_device() instead of kfree()
2018-05-30 07:50:36 +02:00
workqueue: Fix NULL pointer dereference
2017-11-15 15:53:17 +01:00
31ad104de6