linux.git/mm/oom_kill.c, branch v2.6.29

memcg: avoid deadlock caused by race between oom and cpuset_attach

2009-01-08T16:31:09+00:00

mpol_rebind_mm(), which can be called from cpuset_attach(), does
down_write(mm->mmap_sem).  This means down_write(mm->mmap_sem) can be
called under cgroup_mutex.

OTOH, page fault path does down_read(mm->mmap_sem) and calls
mem_cgroup_try_charge_xxx(), which may eventually calls
mem_cgroup_out_of_memory().  And mem_cgroup_out_of_memory() calls
cgroup_lock().  This means cgroup_lock() can be called under
down_read(mm->mmap_sem).

If those two paths race, deadlock can happen.

This patch avoid this deadlock by:
  - remove cgroup_lock() from mem_cgroup_out_of_memory().
  - define new mutex (memcg_tasklist) and serialize mem_cgroup_move_task()
    (->attach handler of memory cgroup) and mem_cgroup_out_of_memory.

Signed-off-by: Daisuke Nishimura 
Reviewed-by: KAMEZAWA Hiroyuki 
Acked-by: Balbir Singh 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

memcg: avoid unnecessary system-wide-oom-killer

2009-01-08T16:31:06+00:00

Current mmtom has new oom function as pagefault_out_of_memory().  It's
added for select bad process rathar than killing current.

When memcg hit limit and calls OOM at page_fault, this handler called and
system-wide-oom handling happens.  (means kernel panics if panic_on_oom is
true....)

To avoid overkill, check memcg's recent behavior before starting
system-wide-oom.

And this patch also fixes to guarantee "don't accnout against process with
TIF_MEMDIE".  This is necessary for smooth OOM.

[akpm@linux-foundation.org: build fix]
Signed-off-by: KAMEZAWA Hiroyuki 
Cc: Li Zefan 
Cc: Balbir Singh 
Cc: Daisuke Nishimura 
Cc: Badari Pulavarty 
Cc: Jan Blunck 
Cc: Hirokazu Takahashi 
Cc: Nick Piggin 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

oom: print triggering task's cpuset and mems allowed

2009-01-06T23:58:59+00:00

When cpusets are enabled, it's necessary to print the triggering task's
set of allowable nodes so the subsequently printed meminfo can be
interpreted correctly.

We also print the task's cpuset name for informational purposes.

[rientjes@google.com: task lock current before dereferencing cpuset]
Cc: Paul Menage 
Cc: Li Zefan 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

oom: fix zone_scan_mutex name

2009-01-06T23:58:58+00:00

zone_scan_mutex is actually a spinlock, so name it appropriately.

Signed-off-by: David Rientjes 
Reviewed-by: KOSAKI Motohiro 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: invoke oom-killer from page fault

2009-01-06T23:58:58+00:00

Rather than have the pagefault handler kill a process directly if it gets
a VM_FAULT_OOM, have it call into the OOM killer.

With increasingly sophisticated oom behaviour (cpusets, memory cgroups,
oom killing throttling, oom priority adjustment or selective disabling,
panic on oom, etc), it's silly to unconditionally kill the faulting
process at page fault time.  Create a hook for pagefault oom path to call
into instead.

Only converted x86 and uml so far.

[akpm@linux-foundation.org: make __out_of_memory() static]
[akpm@linux-foundation.org: fix comment]
Signed-off-by: Nick Piggin 
Cc: Jeff Dike 
Acked-by: Ingo Molnar 
Cc: Thomas Gleixner 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Merge branch 'master' into next

2008-11-14T00:29:12+00:00

Conflicts:
	security/keys/internal.h
	security/keys/process_keys.c
	security/keys/request_key.c

Fixed conflicts above by using the non 'tsk' versions.

Signed-off-by: James Morris

CRED: Use RCU to access another task's creds and to release a task's own creds

2008-11-13T23:39:19+00:00

Use RCU to access another task's creds and to release a task's own creds.
This means that it will be possible for the credentials of a task to be
replaced without another task (a) requiring a full lock to read them, and (b)
seeing deallocated memory.

Signed-off-by: David Howells 
Acked-by: James Morris 
Acked-by: Serge Hallyn 
Signed-off-by: James Morris

CRED: Separate task security context from task_struct

2008-11-13T23:39:16+00:00

Separate the task security context from task_struct.  At this point, the
security data is temporarily embedded in the task_struct with two pointers
pointing to it.

Note that the Alpha arch is altered as it refers to (E)UID and (E)GID in
entry.S via asm-offsets.

With comment fixes Signed-off-by: Marc Dionne 

Signed-off-by: David Howells 
Acked-by: James Morris 
Acked-by: Serge Hallyn 
Signed-off-by: James Morris

The oomkiller calculations make decisions based on capabilities. Since

2008-11-11T11:02:54+00:00

these are not security decisions and LSMs should not record if they fall
the request they should use the new has_capability_noaudit() interface so
the denials will not be recorded.

Signed-off-by: Eric Paris 
Acked-by:  Stephen Smalley 
Signed-off-by: James Morris

mm/oom_kill.c: fix badness() kerneldoc

2008-11-06T23:41:19+00:00

Paramter @mem has been removed since v2.6.26, now delete it's comment.

Signed-off-by: Qinghuang Feng 
Acked-by: Randy Dunlap 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds