diff options
author | Paul Jackson <pj@sgi.com> | 2006-01-14 13:21:06 -0800 |
---|---|---|
committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-01-14 18:27:10 -0800 |
commit | 505970b96e3b7d22177c38e03435a68376628e7a (patch) | |
tree | 5508317e391961355bf3d946a6aac05bb21569eb /mm | |
parent | ed68cb3676bb179768529aeb808403d57295af56 (diff) | |
download | linux-505970b96e3b7d22177c38e03435a68376628e7a.tar.bz2 |
[PATCH] cpuset oom lock fix
The problem, reported in:
http://bugzilla.kernel.org/show_bug.cgi?id=5859
and by various other email messages and lkml posts is that the cpuset hook
in the oom (out of memory) code can try to take a cpuset semaphore while
holding the tasklist_lock (a spinlock).
One must not sleep while holding a spinlock.
The fix seems easy enough - move the cpuset semaphore region outside the
tasklist_lock region.
This required a few lines of mechanism to implement. The oom code where
the locking needs to be changed does not have access to the cpuset locks,
which are internal to kernel/cpuset.c only. So I provided a couple more
cpuset interface routines, available to the rest of the kernel, which
simple take and drop the lock needed here (cpusets callback_sem).
Signed-off-by: Paul Jackson <pj@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'mm')
-rw-r--r-- | mm/oom_kill.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/mm/oom_kill.c b/mm/oom_kill.c index 4748b906aff2..14bd4ec79597 100644 --- a/mm/oom_kill.c +++ b/mm/oom_kill.c @@ -274,6 +274,7 @@ void out_of_memory(gfp_t gfp_mask, int order) show_mem(); } + cpuset_lock(); read_lock(&tasklist_lock); retry: p = select_bad_process(); @@ -284,6 +285,7 @@ retry: /* Found nothing?!?! Either we hang forever, or we panic. */ if (!p) { read_unlock(&tasklist_lock); + cpuset_unlock(); panic("Out of memory and no killable processes...\n"); } @@ -293,6 +295,7 @@ retry: out: read_unlock(&tasklist_lock); + cpuset_unlock(); if (mm) mmput(mm); |