From b43a57bb4dae72e8f7232e7c821a8799eda30022 Mon Sep 17 00:00:00 2001 From: Kirill Korotaev Date: Wed, 6 Dec 2006 20:32:27 -0800 Subject: [PATCH] [PATCH] OOM can panic due to processes stuck in __alloc_pages() 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 Signed-off-by: Kirill Korotaev Cc: Nick Piggin Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/page_alloc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index cd47e8f7bd5b..a840e702722c 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -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 */