mirror of
https://github.com/a52xq-dev/kernel.git
synced 2026-10-18 21:58:11 +07:00
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This adds the pidfd_open() syscall. It allows a caller to retrieve pollable pidfds for a process which did not get created via CLONE_PIDFD, i.e. for a process that is created via traditional fork()/clone() calls that is only referenced by a PID: int pidfd = pidfd_open(1234, 0); ret = pidfd_send_signal(pidfd, SIGSTOP, NULL, 0); With the introduction of pidfds through CLONE_PIDFD it is possible to created pidfds at process creation time. However, a lot of processes get created with traditional PID-based calls such as fork() or clone() (without CLONE_PIDFD). For these processes a caller can currently not create a pollable pidfd. This is a problem for Android's low memory killer (LMK) and service managers such as systemd. Both are examples of tools that want to make use of pidfds to get reliable notification of process exit for non-parents (pidfd polling) and race-free signal sending (pidfd_send_signal()). They intend to switch to this API for process supervision/management as soon as possible. Having no way to get pollable pidfds from PID-only processes is one of the biggest blockers for them in adopting this api. With pidfd_open() making it possible to retrieve pidfds for PID-based processes we enable them to adopt this api. In line with Arnd's recent changes to consolidate syscall numbers across architectures, I have added the pidfd_open() syscall to all architectures at the same time. Signed-off-by: Christian Brauner <christian@brauner.io> Reviewed-by: David Howells <dhowells@redhat.com> Reviewed-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Arnd Bergmann <arnd@arndb.de> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Kees Cook <keescook@chromium.org> Cc: Joel Fernandes (Google) <joel@joelfernandes.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Jann Horn <jannh@google.com> Cc: Andy Lutomirsky <luto@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Aleksa Sarai <cyphar@cyphar.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: linux-api@vger.kernel.org (cherry picked from commit 32fcb426ec001cb6d5a4a195091a8486ea77e2df) Bug: 135608568 Test: test program using syscall(__NR_sys_pidfd_open,..) and poll() Change-Id: I97583cfa441a08585cbedf9a44f982c0d0ee5583 Signed-off-by: Suren Baghdasaryan <surenb@google.com> 
Christian Brauner
authored and
 Joel Fernandes (Google)
commited |
abd43bb345 | |
This patch adds polling support to pidfd. Android low memory killer (LMK) needs to know when a process dies once it is sent the kill signal. It does so by checking for the existence of /proc/pid which is both racy and slow. For example, if a PID is reused between when LMK sends a kill signal and checks for existence of the PID, since the wrong PID is now possibly checked for existence. Using the polling support, LMK will be able to get notified when a process exists in race-free and fast way, and allows the LMK to do other things (such as by polling on other fds) while awaiting the process being killed to die. For notification to polling processes, we follow the same existing mechanism in the kernel used when the parent of the task group is to be notified of a child's death (do_notify_parent). This is precisely when the tasks waiting on a poll of pidfd are also awakened in this patch. We have decided to include the waitqueue in struct pid for the following reasons: 1. The wait queue has to survive for the lifetime of the poll. Including it in task_struct would not be option in this case because the task can be reaped and destroyed before the poll returns. 2. By including the struct pid for the waitqueue means that during de_thread(), the new thread group leader automatically gets the new waitqueue/pid even though its task_struct is different. Appropriate test cases are added in the second patch to provide coverage of all the cases the patch is handling. Cc: Andy Lutomirski <luto@amacapital.net> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Daniel Colascione <dancol@google.com> Cc: Jann Horn <jannh@google.com> Cc: Tim Murray <timmurray@google.com> Cc: Jonathan Kowalski <bl0pbl33p@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Kees Cook <keescook@chromium.org> Cc: David Howells <dhowells@redhat.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: kernel-team@android.com Reviewed-by: Oleg Nesterov <oleg@redhat.com> Co-developed-by: Daniel Colascione <dancol@google.com> Signed-off-by: Daniel Colascione <dancol@google.com> Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org> Signed-off-by: Christian Brauner <christian@brauner.io> (cherry picked from commit b53b0b9d9a613c418057f6cb921c2f40a6f78c24) Bug: 135608568 Test: test program using syscall(__NR_sys_pidfd_open,..) and poll() Change-Id: I0391acb666b34e33ef60a778dffdf12ed3654393 Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Joel Fernandes (Google)
commited |
b3481301f4 | |
commit 1a80dade010c7a7f4885a4c4c2a7ac22cc7b34df upstream.
The failure path removes the allocated PIDs from the wrong namespace.
This could lead to us inadvertently reusing PIDs in the leaf namespace
and leaking PIDs in parent namespaces.
Fixes:
Matthew Wilcox
authored and
 Greg Kroah-Hartman
commited |
a854491995 | |
Make the clone and fork syscalls return EAGAIN when the limit on the number of pids /proc/sys/kernel/pid_max is exceeded. Currently, when the pid_max limit is exceeded, the kernel will return ENOSPC from the fork and clone syscalls. This is contrary to the documented behaviour, which explicitly calls out the pid_max case as one where EAGAIN should be returned. It also leads to really confusing error messages in userspace programs which will complain about a lack of disk space when they fail to create processes/threads for this reason. This error is being returned because alloc_pid() uses the idr api to find a new pid; when there are none available, idr_alloc_cyclic() returns -ENOSPC, and this is being propagated back to userspace. This behaviour has been broken before, and was explicitly fixed in commit 
KJ Tsanaktsidis
authored and
Greg Kroah-Hartman
commited |
f83606f5eb | |
Everywhere except in the pid array we distinguish between a tasks pid and a tasks tgid (thread group id). Even in the enumeration we want that distinction sometimes so we have added __PIDTYPE_TGID. With leader_pid we almost have an implementation of PIDTYPE_TGID in struct signal_struct. Add PIDTYPE_TGID as a first class member of the pid_type enumeration and into the pids array. Then remove the __PIDTYPE_TGID special case and the leader_pid in signal_struct. The net size increase is just an extra pointer added to struct pid and an extra pair of pointers of an hlist_node added to task_struct. The effect on code maintenance is the removal of a number of special cases today and the potential to remove many more special cases as PIDTYPE_TGID gets used to it's fullest. The long term potential is allowing zombie thread group leaders to exit, which will remove a lot more special cases in the code. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> 
Eric W. Biederman
commited |
6883f81aac | |
To access these fields the code always has to go to group leader so going to signal struct is no loss and is actually a fundamental simplification. This saves a little bit of memory by only allocating the pid pointer array once instead of once for every thread, and even better this removes a few potential races caused by the fact that group_leader can be changed by de_thread, while signal_struct can not. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Eric W. Biederman
commited |
2c4704756c | |
The cost is the the same and this removes the need to worry about complications that come from de_thread and group_leader changing. __task_pid_nr_ns has been updated to take advantage of this change. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Eric W. Biederman
commited |
7a36094d61 | |
This results in no change in structure size on 64-bit machines as it fits in the padding between the gfp_t and the void *. 32-bit machines will grow the structure from 8 to 12 bytes. Almost all radix trees are protected with (at least) a spinlock, so as they are converted from radix trees to xarrays, the data structures will shrink again. Initialising the spinlock requires a name for the benefit of lockdep, so RADIX_TREE_INIT() now needs to know the name of the radix tree it's initialising, and so do IDR_INIT() and IDA_INIT(). Also add the xa_lock() and xa_unlock() family of wrappers to make it easier to use the lock. If we could rely on -fplan9-extensions in the compiler, we could avoid all of this syntactic sugar, but that wasn't added until gcc 4.6. Link: http://lkml.kernel.org/r/20180313132639.17387-8-willy@infradead.org Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> Cc: Darrick J. Wong <darrick.wong@oracle.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> 
Matthew Wilcox
authored and
 Linus Torvalds
commited |
f6bb2a2c0b | |
There are several functions that do find_task_by_vpid() followed by get_task_struct(). We can use a helper function instead. Link: http://lkml.kernel.org/r/1509602027-11337-1-git-send-email-rppt@linux.vnet.ibm.com Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com> Acked-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> 
Mike Rapoport
authored and
Linus Torvalds
commited |
2ee0826085 | |
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Merge tag 'init_task-20180117' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs
Pull init_task initializer cleanups from David Howells:
"It doesn't seem useful to have the init_task in a header file rather
than in a normal source file. We could consolidate init_task handling
instead and expand out various macros.
Here's a series of patches that consolidate init_task handling:
(1) Make THREAD_SIZE available to vmlinux.lds for cris, hexagon and
openrisc.
(2) Alter the INIT_TASK_DATA linker script macro to set
init_thread_union and init_stack rather than defining these in C.
Insert init_task and init_thread_into into the init_stack area in
the linker script as appropriate to the configuration, with
different section markers so that they end up correctly ordered.
We can then get merge ia64's init_task.c into the main one.
We then have a bunch of single-use INIT_*() macros that seem only
to be macros because they used to be used per-arch. We can then
expand these in place of the user and get rid of a few lines and
a lot of backslashes.
(3) Expand INIT_TASK() in place.
(4) Expand in place various small INIT_*() macros that are defined
conditionally. Expand them and surround them by #if[n]def/#endif
in the .c file as it takes fewer lines.
(5) Expand INIT_SIGNALS() and INIT_SIGHAND() in place.
(6) Expand INIT_STRUCT_PID in place.
These macros can then be discarded"
* tag 'init_task-20180117' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs:
Expand INIT_STRUCT_PID and remove
Expand the INIT_SIGNALS and INIT_SIGHAND macros and remove
Expand various INIT_* macros and remove
Expand INIT_TASK() in init/init_task.c and remove
Construct init thread stack in the linker script rather than by union
openrisc: Make THREAD_SIZE available to vmlinux.lds
hexagon: Make THREAD_SIZE available to vmlinux.lds
cris: Make THREAD_SIZE available to vmlinux.lds
Linus Torvalds
commited |
49f9c3552c | |
Expand INIT_STRUCT_PID in the single place that uses it and then remove it. There doesn't seem any point in the macro. Signed-off-by: David Howells <dhowells@redhat.com> Tested-by: Tony Luck <tony.luck@intel.com> Tested-by: Will Deacon <will.deacon@arm.com> (arm64) Tested-by: Palmer Dabbelt <palmer@sifive.com> Acked-by: Thomas Gleixner <tglx@linutronix.de> 
David Howells
commited |
e1e871aff3 | |
With the replacement of the pid bitmap and hashtable with an idr in alloc_pid started occassionally failing when allocating the first pid in a pid namespace. Things were not completely reset resulting in the first allocated pid getting the number 2 (not 1). Which further resulted in ns->proc_mnt not getting set and eventually causing an oops in proc_flush_task. Oops: 0000 [#1] SMP CPU: 2 PID: 6743 Comm: trinity-c117 Not tainted 4.15.0-rc4-think+ #2 RIP: 0010:proc_flush_task+0x8e/0x1b0 RSP: 0018:ffffc9000bbffc40 EFLAGS: 00010286 RAX: 0000000000000001 RBX: 0000000000000001 RCX: 00000000fffffffb RDX: 0000000000000000 RSI: ffffc9000bbffc50 RDI: 0000000000000000 RBP: ffffc9000bbffc63 R08: 0000000000000000 R09: 0000000000000002 R10: ffffc9000bbffb70 R11: ffffc9000bbffc64 R12: 0000000000000003 R13: 0000000000000000 R14: 0000000000000003 R15: ffff8804c10d7840 FS: 00007f7cb8965700(0000) GS:ffff88050a200000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 00000003e21ae003 CR4: 00000000001606e0 DR0: 00007fb1d6c22000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: ? release_task+0xaf/0x680 release_task+0xd2/0x680 ? wait_consider_task+0xb82/0xce0 wait_consider_task+0xbe9/0xce0 ? do_wait+0xe1/0x330 do_wait+0x151/0x330 kernel_wait4+0x8d/0x150 ? task_stopped_code+0x50/0x50 SYSC_wait4+0x95/0xa0 ? rcu_read_lock_sched_held+0x6c/0x80 ? syscall_trace_enter+0x2d7/0x340 ? do_syscall_64+0x60/0x210 do_syscall_64+0x60/0x210 entry_SYSCALL64_slow_path+0x25/0x25 RIP: 0033:0x7f7cb82603aa RSP: 002b:00007ffd60770bc8 EFLAGS: 00000246 ORIG_RAX: 000000000000003d RAX: ffffffffffffffda RBX: 00007f7cb6cd4000 RCX: 00007f7cb82603aa RDX: 000000000000000b RSI: 00007ffd60770bd0 RDI: 0000000000007cca RBP: 0000000000007cca R08: 00007f7cb8965700 R09: 00007ffd607c7080 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffd60770bd0 R14: 00007f7cb6cd4058 R15: 00000000cccccccd Code: c1 e2 04 44 8b 60 30 48 8b 40 38 44 8b 34 11 48 c7 c2 60 3a f5 81 44 89 e1 4c 8b 68 58 e8 4b b4 77 00 89 44 24 14 48 8d 74 24 10 <49> 8b 7d 00 e8 b9 6a f9 ff 48 85 c0 74 1a 48 89 c7 48 89 44 24 RIP: proc_flush_task+0x8e/0x1b0 RSP: ffffc9000bbffc40 CR2: 0000000000000000 ---[ end trace 53d67a6481059862 ]--- Improve the quality of the implementation by resetting the place to start allocating pids on failure to allocate the first pid. As improving the quality of the implementation is the goal remove the now unnecesarry disable_pid_allocations call when we fail to mount proc. Fixes:
Eric W. Biederman
commited |
c0ee554906 | |
pidhash is no longer required as all the information can be looked up from idr tree. nr_hashed represented the number of pids that had been hashed. Since, nr_hashed and PIDNS_HASH_ADDING are no longer relevant, it has been renamed to pid_allocated and PIDNS_ADDING respectively. [gs051095@gmail.com: v6] Link: http://lkml.kernel.org/r/1507760379-21662-3-git-send-email-gs051095@gmail.com Link: http://lkml.kernel.org/r/1507583624-22146-3-git-send-email-gs051095@gmail.com Signed-off-by: Gargi Sharma <gs051095@gmail.com> Reviewed-by: Rik van Riel <riel@redhat.com> Tested-by: Tony Luck <tony.luck@intel.com> [ia64] Cc: Julia Lawall <julia.lawall@lip6.fr> Cc: Ingo Molnar <mingo@kernel.org> Cc: Pavel Tatashin <pasha.tatashin@oracle.com> Cc: Kirill Tkhai <ktkhai@virtuozzo.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: Christoph Hellwig <hch@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> 
Gargi Sharma
authored and
Linus Torvalds
commited |
e8cfbc245e | |
Patch series "Replacing PID bitmap implementation with IDR API", v4.
This series replaces kernel bitmap implementation of PID allocation with
IDR API. These patches are written to simplify the kernel by replacing
custom code with calls to generic code.
The following are the stats for pid and pid_namespace object files
before and after the replacement. There is a noteworthy change between
the IDR and bitmap implementation.
Before
text data bss dec hex filename
8447 3894 64 12405 3075 kernel/pid.o
After
text data bss dec hex filename
3397 304 0 3701 e75 kernel/pid.o
Before
text data bss dec hex filename
5692 1842 192 7726 1e2e kernel/pid_namespace.o
After
text data bss dec hex filename
2854 216 16 3086 c0e kernel/pid_namespace.o
The following are the stats for ps, pstree and calling readdir on /proc
for 10,000 processes.
ps:
With IDR API With bitmap
real 0m1.479s 0m2.319s
user 0m0.070s 0m0.060s
sys 0m0.289s 0m0.516s
pstree:
With IDR API With bitmap
real 0m1.024s 0m1.794s
user 0m0.348s 0m0.612s
sys 0m0.184s 0m0.264s
proc:
With IDR API With bitmap
real 0m0.059s 0m0.074s
user 0m0.000s 0m0.004s
sys 0m0.016s 0m0.016s
This patch (of 2):
Replace the current bitmap implementation for Process ID allocation.
Functions that are no longer required, for example, free_pidmap(),
alloc_pidmap(), etc. are removed. The rest of the functions are
modified to use the IDR API. The change was made to make the PID
allocation less complex by replacing custom code with calls to generic
API.
[gs051095@gmail.com: v6]
Link: http://lkml.kernel.org/r/1507760379-21662-2-git-send-email-gs051095@gmail.com
[avagin@openvz.org: restore the old behaviour of the ns_last_pid sysctl]
Link: http://lkml.kernel.org/r/20171106183144.16368-1-avagin@openvz.org
Link: http://lkml.kernel.org/r/1507583624-22146-2-git-send-email-gs051095@gmail.com
Signed-off-by: Gargi Sharma <gs051095@gmail.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Cc: Julia Lawall <julia.lawall@lip6.fr>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Pavel Tatashin <pasha.tatashin@oracle.com>
Cc: Kirill Tkhai <ktkhai@virtuozzo.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Gargi Sharma
authored and
Linus Torvalds
commited |
95846ecf9d | |
This was reported many times, and this was even mentioned in commit
Oleg Nesterov
authored and
Linus Torvalds
commited |
dd1c1f2f20 | |
After commit
Kefeng Wang
authored and
Linus Torvalds
commited |
27e37d84e5 | |
Update dcache, inode, pid, mountpoint, and mount hash tables to use HASH_ZERO, and remove initialization after allocations. In case of places where HASH_EARLY was used such as in __pv_init_lock_hash the zeroed hash table was already assumed, because memblock zeroes the memory. CPU: SPARC M6, Memory: 7T Before fix: Dentry cache hash table entries: 1073741824 Inode-cache hash table entries: 536870912 Mount-cache hash table entries: 16777216 Mountpoint-cache hash table entries: 16777216 ftrace: allocating 20414 entries in 40 pages Total time: 11.798s After fix: Dentry cache hash table entries: 1073741824 Inode-cache hash table entries: 536870912 Mount-cache hash table entries: 16777216 Mountpoint-cache hash table entries: 16777216 ftrace: allocating 20414 entries in 40 pages Total time: 3.198s CPU: Intel Xeon E5-2630, Memory: 2.2T: Before fix: Dentry cache hash table entries: 536870912 Inode-cache hash table entries: 268435456 Mount-cache hash table entries: 8388608 Mountpoint-cache hash table entries: 8388608 CPU: Physical Processor ID: 0 Total time: 3.245s After fix: Dentry cache hash table entries: 536870912 Inode-cache hash table entries: 268435456 Mount-cache hash table entries: 8388608 Mountpoint-cache hash table entries: 8388608 CPU: Physical Processor ID: 0 Total time: 3.244s Link: http://lkml.kernel.org/r/1488432825-92126-4-git-send-email-pasha.tatashin@oracle.com Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com> Reviewed-by: Babu Moger <babu.moger@oracle.com> Cc: David Miller <davem@davemloft.net> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> 
Pavel Tatashin
authored and
Linus Torvalds
commited |
3d375d7859 | |
alloc_pidmap() advances pid_namespace::last_pid. When first pid
allocation fails, then next created process will have pid 2 and
pid_ns_prepare_proc() won't be called. So, pid_namespace::proc_mnt will
never be initialized (not to mention that there won't be a child
reaper).
I saw crash stack of such case on kernel 3.10:
BUG: unable to handle kernel NULL pointer dereference at (null)
IP: proc_flush_task+0x8f/0x1b0
Call Trace:
release_task+0x3f/0x490
wait_consider_task.part.10+0x7ff/0xb00
do_wait+0x11f/0x280
SyS_wait4+0x7d/0x110
We may fix this by restore of last_pid in 0 or by prohibiting of futher
allocations. Since there was a similar issue in Oleg Nesterov's commit
Kirill Tkhai
authored and
Linus Torvalds
commited |
8896c23d2e | |
We are going to split <linux/sched/task.h> out of <linux/sched.h>, which will have to be picked up from other headers and a couple of .c files. Create a trivial placeholder <linux/sched/task.h> file that just maps to <linux/sched.h> to make this patch obviously correct and bisectable. Include the new header in the files that are going to need it. Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> 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> 
Ingo Molnar
commited |
299300258d | |
Since we need to change the implementation, stop exposing internals. Provide KREF_INIT() to allow static initialization of struct kref. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.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 Signed-off-by: Ingo Molnar <mingo@kernel.org> 
Peter Zijlstra
authored and
Ingo Molnar
commited |
1e24edca05 | |
Most users of IS_ERR_VALUE() in the kernel are wrong, as they
pass an 'int' into a function that takes an 'unsigned long'
argument. This happens to work because the type is sign-extended
on 64-bit architectures before it gets converted into an
unsigned type.
However, anything that passes an 'unsigned short' or 'unsigned int'
argument into IS_ERR_VALUE() is guaranteed to be broken, as are
8-bit integers and types that are wider than 'unsigned long'.
Andrzej Hajda has already fixed a lot of the worst abusers that
were causing actual bugs, but it would be nice to prevent any
users that are not passing 'unsigned long' arguments.
This patch changes all users of IS_ERR_VALUE() that I could find
on 32-bit ARM randconfig builds and x86 allmodconfig. For the
moment, this doesn't change the definition of IS_ERR_VALUE()
because there are probably still architecture specific users
elsewhere.
Almost all the warnings I got are for files that are better off
using 'if (err)' or 'if (err < 0)'.
The only legitimate user I could find that we get a warning for
is the (32-bit only) freescale fman driver, so I did not remove
the IS_ERR_VALUE() there but changed the type to 'unsigned long'.
For 9pfs, I just worked around one user whose calling conventions
are so obscure that I did not dare change the behavior.
I was using this definition for testing:
#define IS_ERR_VALUE(x) ((unsigned long*)NULL == (typeof (x)*)NULL && \
unlikely((unsigned long long)(x) >= (unsigned long long)(typeof(x))-MAX_ERRNO))
which ends up making all 16-bit or wider types work correctly with
the most plausible interpretation of what IS_ERR_VALUE() was supposed
to return according to its users, but also causes a compile-time
warning for any users that do not pass an 'unsigned long' argument.
I suggested this approach earlier this year, but back then we ended
up deciding to just fix the users that are obviously broken. After
the initial warning that caused me to get involved in the discussion
(fs/gfs2/dir.c) showed up again in the mainline kernel, Linus
asked me to send the whole thing again.
[ Updated the 9p parts as per Al Viro - Linus ]
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Andrzej Hajda <a.hajda@samsung.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: https://lkml.org/lkml/2016/1/7/363
Link: https://lkml.org/lkml/2016/5/27/486
Acked-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org> # For nvmem part
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Arnd Bergmann
authored and
Linus Torvalds
commited |
287980e49f | |
Pull scheduler fixes from Thomas Gleixner: "Three small fixes in the scheduler/core: - use after free in the numa code - crash in the numa init code - a simple spelling fix" * 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: pid: Fix spelling in comments sched/numa: Fix use-after-free bug in the task_numa_compare sched: Fix crash in sched_init_numa()
Linus Torvalds
commited |
7ab85d4a85 | |
Accidentally discovered this typo when I studied this module. Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com> Cc: Hanjun Guo <guohanjun@huawei.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tianhong Ding <dingtianhong@huawei.com> Cc: Xinwei Hu <huxinwei@huawei.com> Cc: Zefan Li <lizefan@huawei.com> Link: http://lkml.kernel.org/r/1454119457-11272-1-git-send-email-thunder.leizhen@huawei.com Signed-off-by: Ingo Molnar <mingo@kernel.org> 
Zhen Lei
authored and
Ingo Molnar
commited |
840d6fe742 | |
Mark those kmem allocations that are known to be easily triggered from userspace as __GFP_ACCOUNT/SLAB_ACCOUNT, which makes them accounted to memcg. For the list, see below: - threadinfo - task_struct - task_delay_info - pid - cred - mm_struct - vm_area_struct and vm_region (nommu) - anon_vma and anon_vma_chain - signal_struct - sighand_struct - fs_struct - files_struct - fdtable and fdtable->full_fds_bits - dentry and external_name - inode for all filesystems. This is the most tedious part, because most filesystems overwrite the alloc_inode method. The list is far from complete, so feel free to add more objects. Nevertheless, it should be close to "account everything" approach and keep most workloads within bounds. Malevolent users will be able to breach the limit, but this was possible even with the former "account everything" approach (simply because it did not account everything in fact). [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Vladimir Davydov <vdavydov@virtuozzo.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Tejun Heo <tj@kernel.org> Cc: Greg Thelen <gthelen@google.com> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> 
Vladimir Davydov
authored and
Linus Torvalds
commited |
5d097056c9 | |
I got a crash during a "perf top" session that was caused by a race in
__task_pid_nr_ns() :
pid_nr_ns() was inlined, but apparently compiler chose to read
task->pids[type].pid twice, and the pid->level dereference crashed
because we got a NULL pointer at the second read :
if (pid && ns->level <= pid->level) { // CRASH
Just use RCU API properly to solve this race, and not worry about "perf
top" crashing hosts :(
get_task_pid() can benefit from same fix.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Eric Dumazet
authored and
Linus Torvalds
commited |
81b1a832d7 | |
This commit renames rcu_lockdep_assert() to RCU_LOCKDEP_WARN() for consistency with the WARN() series of macros. This also requires inverting the sense of the conditional, which this commit also does. Reported-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Ingo Molnar <mingo@kernel.org> 
Paul E. McKenney
commited |
f78f5b90c4 | |
copy_process will report any failure in alloc_pid as ENOMEM currently which is misleading because the pid allocation might fail not only when the memory is short but also when the pid space is consumed already. The current man page even mentions this case: : EAGAIN : : A system-imposed limit on the number of threads was encountered. : There are a number of limits that may trigger this error: the : RLIMIT_NPROC soft resource limit (set via setrlimit(2)), which : limits the number of processes and threads for a real user ID, was : reached; the kernel's system-wide limit on the number of processes : and threads, /proc/sys/kernel/threads-max, was reached (see : proc(5)); or the maximum number of PIDs, /proc/sys/kernel/pid_max, : was reached (see proc(5)). so the current behavior is also incorrect wrt. documentation. POSIX man page also suggest returing EAGAIN when the process count limit is reached. This patch simply propagates error code from alloc_pid and makes sure we return -EAGAIN due to reservation failure. This will make behavior of fork closer to both our documentation and POSIX. alloc_pid might alsoo fail when the reaper in the pid namespace is dead (the namespace basically disallows all new processes) and there is no good error code which would match documented ones. We have traditionally returned ENOMEM for this case which is misleading as well but as per Eric W. Biederman this behavior is documented in man pid_namespaces(7) : If the "init" process of a PID namespace terminates, the kernel : terminates all of the processes in the namespace via a SIGKILL signal. : This behavior reflects the fact that the "init" process is essential for : the correct operation of a PID namespace. In this case, a subsequent : fork(2) into this PID namespace will fail with the error ENOMEM; it is : not possible to create a new processes in a PID namespace whose "init" : process has terminated. and introducing a new error code would be too risky so let's stick to ENOMEM for this case. Signed-off-by: Michal Hocko <mhocko@suse.cz> Cc: Oleg Nesterov <oleg@redhat.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Michael Kerrisk <mtk.manpages@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> 
Michal Hocko
authored and
Linus Torvalds
commited |
35f71bc0a0 | |
Pull vfs pile #2 from Al Viro: "Next pile (and there'll be one or two more). The large piece in this one is getting rid of /proc/*/ns/* weirdness; among other things, it allows to (finally) make nameidata completely opaque outside of fs/namei.c, making for easier further cleanups in there" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: coda_venus_readdir(): use file_inode() fs/namei.c: fold link_path_walk() call into path_init() path_init(): don't bother with LOOKUP_PARENT in argument fs/namei.c: new helper (path_cleanup()) path_init(): store the "base" pointer to file in nameidata itself make default ->i_fop have ->open() fail with ENXIO make nameidata completely opaque outside of fs/namei.c kill proc_ns completely take the targets of /proc/*/ns/* symlinks to separate fs bury struct proc_ns in fs/proc copy address of proc_ns_ops into ns_common new helpers: ns_alloc_inum/ns_free_inum make proc_ns_operations work with struct ns_common * instead of void * switch the rest of proc_ns_operations to working with &...->ns netns: switch ->get()/->put()/->install()/->inum() to working with &net->ns make mntns ->get()/->put()/->install()/->inum() work with &mnt_ns->ns common object embedded into various struct ....ns
Linus Torvalds
commited |
603ba7e41b | |
alloc_pid() does get_pid_ns() beforehand but forgets to put_pid_ns() if it fails because disable_pid_allocation() was called by the exiting child_reaper. We could simply move get_pid_ns() down to successful return, but this fix tries to be as trivial as possible. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Reviewed-by: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Aaron Tomlin <atomlin@redhat.com> Cc: Pavel Emelyanov <xemul@parallels.com> Cc: Serge Hallyn <serge.hallyn@ubuntu.com> Cc: Sterling Alexander <stalexan@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Oleg Nesterov
authored and
Linus Torvalds
commited |
24c037ebf5 | |
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> 
Al Viro
commited |
33c429405a | |
for now - just move corresponding ->proc_inum instances over there Acked-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Al Viro
commited |
435d5f4bb2 | |
"case 0" in free_pid() assumes that disable_pid_allocation() should clear PIDNS_HASH_ADDING before the last pid goes away. However this doesn't happen if the first fork() fails to create the child reaper which should call disable_pid_allocation(). Signed-off-by: Oleg Nesterov <oleg@redhat.com> Reviewed-by: "Eric W. Biederman" <ebiederm@xmission.com> Cc: "Serge E. Hallyn" <serge@hallyn.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Oleg Nesterov
authored and
Linus Torvalds
commited |
314a8ad0f1 | |
Serge Hallyn <serge.hallyn@ubuntu.com> writes:
> Since commit
Eric W. Biederman
commited |
a606488513 | |
Move statement to static initilization of init_pid_ns. Signed-off-by: Raphael S. Carvalho <raphael.scarv@gmail.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Acked-by: Serge Hallyn <serge.hallyn@canonical.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> 
Raphael S. Carvalho
authored and
Linus Torvalds
commited |
8f75af44ee | |
copy_process() adds the new child to thread_group/init_task.tasks list and then does attach_pid(child, PIDTYPE_PID). This means that the lockless next_thread() or next_task() can see this thread with the wrong pid. Say, "ls /proc/pid/task" can list the same inode twice. We could move attach_pid(child, PIDTYPE_PID) up, but in this case find_task_by_vpid() can find the new thread before it was fully initialized. And this is already true for PIDTYPE_PGID/PIDTYPE_SID, With this patch copy_process() initializes child->pids[*].pid first, then calls attach_pid() to insert the task into the pid->tasks list. attach_pid() no longer need the "struct pid*" argument, it is always called after pid_link->pid was already set. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Michal Hocko <mhocko@suse.cz> Cc: Pavel Emelyanov <xemul@parallels.com> Cc: Sergey Dyasly <dserrg@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Oleg Nesterov
authored and
Linus Torvalds
commited |
8190773985 | |
Pull VFS updates from Al Viro,
Misc cleanups all over the place, mainly wrt /proc interfaces (switch
create_proc_entry to proc_create(), get rid of the deprecated
create_proc_read_entry() in favor of using proc_create_data() and
seq_file etc).
7kloc removed.
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (204 commits)
don't bother with deferred freeing of fdtables
proc: Move non-public stuff from linux/proc_fs.h to fs/proc/internal.h
proc: Make the PROC_I() and PDE() macros internal to procfs
proc: Supply a function to remove a proc entry by PDE
take cgroup_open() and cpuset_open() to fs/proc/base.c
ppc: Clean up scanlog
ppc: Clean up rtas_flash driver somewhat
hostap: proc: Use remove_proc_subtree()
drm: proc: Use remove_proc_subtree()
drm: proc: Use minor->index to label things, not PDE->name
drm: Constify drm_proc_list[]
zoran: Don't print proc_dir_entry data in debug
reiserfs: Don't access the proc_dir_entry in r_open(), r_start() r_show()
proc: Supply an accessor for getting the data from a PDE's parent
airo: Use remove_proc_subtree()
rtl8192u: Don't need to save device proc dir PDE
rtl8187se: Use a dir under /proc/net/r8180/
proc: Add proc_mkdir_data()
proc: Move some bits from linux/proc_fs.h to linux/{of.h,signal.h,tty.h}
proc: Move PDE_NET() to fs/proc/proc_net.c
...
Linus Torvalds
commited |
20b4fb4852 | |
Split the proc namespace stuff out into linux/proc_ns.h. Signed-off-by: David Howells <dhowells@redhat.com> cc: netdev@vger.kernel.org cc: Serge E. Hallyn <serge.hallyn@ubuntu.com> cc: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
David Howells
authored and
Al Viro
commited |
0bb80f2405 | |
Move BITS_PER_PAGE from pid_namespace.c to pid_namespace.h, since we can simplify the define PID_MAP_ENTRIES by using the BITS_PER_PAGE. [akpm@linux-foundation.org: kernel/pid.c:54:1: warning: "BITS_PER_PAGE" redefined] Signed-off-by: Raphael S.Carvalho <raphael.scarv@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Raphael S.Carvalho
authored and
Linus Torvalds
commited |
5cc5445164 | |
find_next_offset() searches for an available "cleaned bit" in the respective pid bitmap (page), so returns the offset if found, otherwise it returns a value equals to BITS_PER_PAGE. For example, suppose find_next_offset didn't find any available bit, so there's no purpose to call mk_pid (Wasteful Cpu Cycles). Therefore, I found it could be better to call mk_pid after the checking (offset < BITS_PER_PAGE) returned sucessfully! Another point: If (offset < BITS_PER_PAGE) results in a "failure", then mk_pid would be called again afterwards. [akpm@linux-foundation.org: simplify code] Signed-off-by: Raphael S. Carvalho <raphael.scarv@gmail.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Serge Hallyn <serge.hallyn@canonical.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Raphael S. Carvalho
authored and
Linus Torvalds
commited |
8db049b3d6 | |
I'm not sure why, but the hlist for each entry iterators were conceived
list_for_each_entry(pos, head, member)
The hlist ones were greedy and wanted an extra parameter:
hlist_for_each_entry(tpos, pos, head, member)
Why did they need an extra pos parameter? I'm not quite sure. Not only
they don't really need it, it also prevents the iterator from looking
exactly like the list iterator, which is unfortunate.
Besides the semantic patch, there was some manual work required:
- Fix up the actual hlist iterators in linux/list.h
- Fix up the declaration of other iterators based on the hlist ones.
- A very small amount of places were using the 'node' parameter, this
was modified to use 'obj->member' instead.
- Coccinelle didn't handle the hlist_for_each_entry_safe iterator
properly, so those had to be fixed up manually.
The semantic patch which is mostly the work of Peter Senna Tschudin is here:
@@
iterator name hlist_for_each_entry, hlist_for_each_entry_continue, hlist_for_each_entry_from, hlist_for_each_entry_rcu, hlist_for_each_entry_rcu_bh, hlist_for_each_entry_continue_rcu_bh, for_each_busy_worker, ax25_uid_for_each, ax25_for_each, inet_bind_bucket_for_each, sctp_for_each_hentry, sk_for_each, sk_for_each_rcu, sk_for_each_from, sk_for_each_safe, sk_for_each_bound, hlist_for_each_entry_safe, hlist_for_each_entry_continue_rcu, nr_neigh_for_each, nr_neigh_for_each_safe, nr_node_for_each, nr_node_for_each_safe, for_each_gfn_indirect_valid_sp, for_each_gfn_sp, for_each_host;
type T;
expression a,c,d,e;
identifier b;
statement S;
@@
-T b;
<+... when != b
(
hlist_for_each_entry(a,
- b,
c, d) S
|
hlist_for_each_entry_continue(a,
- b,
c) S
|
hlist_for_each_entry_from(a,
- b,
c) S
|
hlist_for_each_entry_rcu(a,
- b,
c, d) S
|
hlist_for_each_entry_rcu_bh(a,
- b,
c, d) S
|
hlist_for_each_entry_continue_rcu_bh(a,
- b,
c) S
|
for_each_busy_worker(a, c,
- b,
d) S
|
ax25_uid_for_each(a,
- b,
c) S
|
ax25_for_each(a,
- b,
c) S
|
inet_bind_bucket_for_each(a,
- b,
c) S
|
sctp_for_each_hentry(a,
- b,
c) S
|
sk_for_each(a,
- b,
c) S
|
sk_for_each_rcu(a,
- b,
c) S
|
sk_for_each_from
-(a, b)
+(a)
S
+ sk_for_each_from(a) S
|
sk_for_each_safe(a,
- b,
c, d) S
|
sk_for_each_bound(a,
- b,
c) S
|
hlist_for_each_entry_safe(a,
- b,
c, d, e) S
|
hlist_for_each_entry_continue_rcu(a,
- b,
c) S
|
nr_neigh_for_each(a,
- b,
c) S
|
nr_neigh_for_each_safe(a,
- b,
c, d) S
|
nr_node_for_each(a,
- b,
c) S
|
nr_node_for_each_safe(a,
- b,
c, d) S
|
- for_each_gfn_sp(a, c, d, b) S
+ for_each_gfn_sp(a, c, d) S
|
- for_each_gfn_indirect_valid_sp(a, c, d, b) S
+ for_each_gfn_indirect_valid_sp(a, c, d) S
|
for_each_host(a,
- b,
c) S
|
for_each_host_safe(a,
- b,
c, d) S
|
for_each_mesh_entry(a,
- b,
c, d) S
)
...+>
[akpm@linux-foundation.org: drop bogus change from net/ipv4/raw.c]
[akpm@linux-foundation.org: drop bogus hunk from net/ipv6/raw.c]
[akpm@linux-foundation.org: checkpatch fixes]
[akpm@linux-foundation.org: fix warnings]
[akpm@linux-foudnation.org: redo intrusive kvm changes]
Tested-by: Peter Senna Tschudin <peter.senna@gmail.com>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Sasha Levin
authored and
Linus Torvalds
commited |
b67bfe0d42 | |
We're forgetting to reenable local interrupts on an error path. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> Reported-by: Josh Boyer <jwboyer@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Eric W. Biederman
authored and
Linus Torvalds
commited |
6e6668845f | |
Oleg pointed out that in a pid namespace the sequence. - pid 1 becomes a zombie - setns(thepidns), fork,... - reaping pid 1. - The injected processes exiting. Can lead to processes attempting access their child reaper and instead following a stale pointer. That waitpid for init can return before all of the processes in the pid namespace have exited is also unfortunate. Avoid these problems by disabling the allocation of new pids in a pid namespace when init dies, instead of when the last process in a pid namespace is reaped. Pointed-out-by: Oleg Nesterov <oleg@redhat.com> Reviewed-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Eric W. Biederman
commited |
c876ad7682 | |
Merge misc patches from Andrew Morton: "Incoming: - lots of misc stuff - backlight tree updates - lib/ updates - Oleg's percpu-rwsem changes - checkpatch - rtc - aoe - more checkpoint/restart support I still have a pile of MM stuff pending - Pekka should be merging later today after which that is good to go. A number of other things are twiddling thumbs awaiting maintainer merges." * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (180 commits) scatterlist: don't BUG when we can trivially return a proper error. docs: update documentation about /proc/<pid>/fdinfo/<fd> fanotify output fs, fanotify: add @mflags field to fanotify output docs: add documentation about /proc/<pid>/fdinfo/<fd> output fs, notify: add procfs fdinfo helper fs, exportfs: add exportfs_encode_inode_fh() helper fs, exportfs: escape nil dereference if no s_export_op present fs, epoll: add procfs fdinfo helper fs, eventfd: add procfs fdinfo helper procfs: add ability to plug in auxiliary fdinfo providers tools/testing/selftests/kcmp/kcmp_test.c: print reason for failure in kcmp_test breakpoint selftests: print failure status instead of cause make error kcmp selftests: print fail status instead of cause make error kcmp selftests: make run_tests fix mem-hotplug selftests: print failure status instead of cause make error cpu-hotplug selftests: print failure status instead of cause make error mqueue selftests: print failure status instead of cause make error vm selftests: print failure status instead of cause make error ubifs: use prandom_bytes mtd: nandsim: use prandom_bytes ...
Linus Torvalds
commited |
848b81415c | |
Since commit
Gao feng
authored and
Linus Torvalds
commited |
a5ba911ec3 | |
Pull user namespace changes from Eric Biederman:
"While small this set of changes is very significant with respect to
containers in general and user namespaces in particular. The user
space interface is now complete.
This set of changes adds support for unprivileged users to create user
namespaces and as a user namespace root to create other namespaces.
The tyranny of supporting suid root preventing unprivileged users from
using cool new kernel features is broken.
This set of changes completes the work on setns, adding support for
the pid, user, mount namespaces.
This set of changes includes a bunch of basic pid namespace
cleanups/simplifications. Of particular significance is the rework of
the pid namespace cleanup so it no longer requires sending out
tendrils into all kinds of unexpected cleanup paths for operation. At
least one case of broken error handling is fixed by this cleanup.
The files under /proc/<pid>/ns/ have been converted from regular files
to magic symlinks which prevents incorrect caching by the VFS,
ensuring the files always refer to the namespace the process is
currently using and ensuring that the ptrace_mayaccess permission
checks are always applied.
The files under /proc/<pid>/ns/ have been given stable inode numbers
so it is now possible to see if different processes share the same
namespaces.
Through the David Miller's net tree are changes to relax many of the
permission checks in the networking stack to allowing the user
namespace root to usefully use the networking stack. Similar changes
for the mount namespace and the pid namespace are coming through my
tree.
Two small changes to add user namespace support were commited here adn
in David Miller's -net tree so that I could complete the work on the
/proc/<pid>/ns/ files in this tree.
Work remains to make it safe to build user namespaces and 9p, afs,
ceph, cifs, coda, gfs2, ncpfs, nfs, nfsd, ocfs2, and xfs so the
Kconfig guard remains in place preventing that user namespaces from
being built when any of those filesystems are enabled.
Future design work remains to allow root users outside of the initial
user namespace to mount more than just /proc and /sys."
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (38 commits)
proc: Usable inode numbers for the namespace file descriptors.
proc: Fix the namespace inode permission checks.
proc: Generalize proc inode allocation
userns: Allow unprivilged mounts of proc and sysfs
userns: For /proc/self/{uid,gid}_map derive the lower userns from the struct file
procfs: Print task uids and gids in the userns that opened the proc file
userns: Implement unshare of the user namespace
userns: Implent proc namespace operations
userns: Kill task_user_ns
userns: Make create_new_namespaces take a user_ns parameter
userns: Allow unprivileged use of setns.
userns: Allow unprivileged users to create new namespaces
userns: Allow setting a userns mapping to your current uid.
userns: Allow chown and setgid preservation
userns: Allow unprivileged users to create user namespaces.
userns: Ignore suid and sgid on binaries if the uid or gid can not be mapped
userns: fix return value on mntns_install() failure
vfs: Allow unprivileged manipulation of the mount namespace.
vfs: Only support slave subtrees across different user namespaces
vfs: Add a user namespace reference from struct mnt_namespace
...
Linus Torvalds
commited |
6a2b60b17b | |
I've legally changed my name with New York State, the US Social Security Administration, et al. This patch propagates the name change and change in initials and login to comments in the kernel source as well. Signed-off-by: Nadia Yvette Chambers <nyc@holomorphy.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz> 
Nadia Yvette Chambers
authored and
 Jiri Kosina
commited |
6d49e352ae | |
Assign a unique proc inode to each namespace, and use that inode number to ensure we only allocate at most one proc inode for every namespace in proc. A single proc inode per namespace allows userspace to test to see if two processes are in the same namespace. This has been a long requested feature and only blocked because a naive implementation would put the id in a global space and would ultimately require having a namespace for the names of namespaces, making migration and certain virtualization tricks impossible. We still don't have per superblock inode numbers for proc, which appears necessary for application unaware checkpoint/restart and migrations (if the application is using namespace file descriptors) but that is now allowd by the design if it becomes important. I have preallocated the ipc and uts initial proc inode numbers so their structures can be statically initialized. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Eric W. Biederman
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98f842e675 | |
Looking at pid_ns->nr_hashed is a bit simpler and it works for disjoint process trees that an unshare or a join of a pid_namespace may create. Acked-by: "Serge E. Hallyn" <serge@hallyn.com> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Eric W. Biederman
commited |
af4b8a83ad | |
Set nr_hashed to -1 just before we schedule the work to cleanup proc. Test nr_hashed just before we hash a new pid and if nr_hashed is < 0 fail. This guaranteees that processes never enter a pid namespaces after we have cleaned up the state to support processes in a pid namespace. Currently sending SIGKILL to all of the process in a pid namespace as init exists gives us this guarantee but we need something a little stronger to support unsharing and joining a pid namespace. Acked-by: "Serge E. Hallyn" <serge@hallyn.com> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Eric W. Biederman
commited |
5e1182deb8 | |
Track the number of pids in the proc hash table. When the number of pids goes to 0 schedule work to unmount the kernel mount of proc. Move the mount of proc into alloc_pid when we allocate the pid for init. Remove the surprising calls of pid_ns_release proc in fork and proc_flush_task. Those code paths really shouldn't know about proc namespace implementation details and people have demonstrated several times that finding and understanding those code paths is difficult and non-obvious. Because of the call path detach pid is alwasy called with the rtnl_lock held free_pid is not allowed to sleep, so the work to unmounting proc is moved to a work queue. This has the side benefit of not blocking the entire world waiting for the unnecessary rcu_barrier in deactivate_locked_super. In the process of making the code clear and obvious this fixes a bug reported by Gao feng <gaofeng@cn.fujitsu.com> where we would leak a mount of proc during clone(CLONE_NEWPID|CLONE_NEWNET) if copy_pid_ns succeeded and copy_net_ns failed. Acked-by: "Serge E. Hallyn" <serge@hallyn.com> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Eric W. Biederman
commited |
0a01f2cc39 |