From: Kirill Korotaev 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 --- mm/page_alloc.c | 2 +- 1 files changed, 1 insertion(+), 1 deletion(-) diff -puN mm/page_alloc.c~oom-can-panic-due-to-processes-stuck-in-__alloc_pages mm/page_alloc.c --- a/mm/page_alloc.c~oom-can-panic-due-to-processes-stuck-in-__alloc_pages +++ a/mm/page_alloc.c @@ -1184,6 +1184,7 @@ 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)) { @@ -1205,7 +1206,6 @@ nofail_alloc: if (!wait) goto nopage; -rebalance: cond_resched(); /* We now go into synchronous reclaim */ _