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[PATCH] OOM can panic due to processes stuck in __alloc_pages()

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OOM can panic due to the processes stuck in __alloc_pages() doing infinite
rebalance loop while no memory can be reclaimed.  OOM killer tries to kill
some processes, but unfortunetaly, rebalance label was moved by someone
below the TIF_MEMDIE check, so buddy allocator doesn't see that process is
OOM-killed and it can simply fail the allocation :/

Observed in reality on RHEL4(2.6.9)+OpenVZ kernel when a user doing some
memory allocation tricks triggered OOM panic.

Signed-off-by: Denis Lunev <den@sw.ru>
Signed-off-by: Kirill Korotaev <dev@openvz.org>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Kirill Korotaev 2006-12-06 20:32:27 -08:00 committed by Linus Torvalds
parent a3eea484f7
commit b43a57bb4d
1 changed files with 1 additions and 1 deletions
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2
mm/page_alloc.c
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@ -1180,6 +1180,7 @@ __alloc_pages(gfp_t gfp_mask, unsigned int order,
/* This allocation should allow future memory freeing. */
rebalance:
if (((p->flags & PF_MEMALLOC) || unlikely(test_thread_flag(TIF_MEMDIE)))
&& !in_interrupt()) {
if (!(gfp_mask & __GFP_NOMEMALLOC)) {
@ -1201,7 +1202,6 @@ __alloc_pages(gfp_t gfp_mask, unsigned int order,
if (!wait)
goto nopage;
rebalance:
cond_resched();
/* We now go into synchronous reclaim */