| [PATCH]: OOM can panic due to processes stuck in __alloc_pages() [message #8290] |
Mon, 13 November 2006 19:05  |
Kirill Korotaev
Messages: 137
Registered: January 2006
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Senior Member |
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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>
--- ./mm/page_alloc.c.oomx 2006-11-08 17:44:16.000000000 +0300
+++ ./mm/page_alloc.c 2006-11-13 21:57:33.000000000 +0300
@@ -1251,6 +1251,7 @@ restart:
/* 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)) {
@@ -1272,7 +1273,6 @@ nofail_alloc:
if (!wait)
goto nopage;
-rebalance:
cond_resched();
/* We now go into synchronous reclaim */
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