From mboxrd@z Thu Jan 1 00:00:00 1970 From: akpm@linux-foundation.org Subject: + oom-avoid-divide-by-zero.patch added to -mm tree Date: Wed, 28 Apr 2010 11:33:17 -0700 Message-ID: <201004281833.o3SIXHvB012391@imap1.linux-foundation.org> Reply-To: linux-kernel@vger.kernel.org Return-path: Received: from smtp1.linux-foundation.org ([140.211.169.13]:60528 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754363Ab0D1SeE (ORCPT ); Wed, 28 Apr 2010 14:34:04 -0400 Sender: mm-commits-owner@vger.kernel.org List-Id: mm-commits@vger.kernel.org To: mm-commits@vger.kernel.org Cc: rientjes@google.com, gthelen@google.com, kamezawa.hiroyu@jp.fujitsu.com The patch titled oom: avoid divide by zero has been added to the -mm tree. Its filename is oom-avoid-divide-by-zero.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** See http://userweb.kernel.org/~akpm/stuff/added-to-mm.txt to find out what to do about this The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/ ------------------------------------------------------ Subject: oom: avoid divide by zero From: David Rientjes It's evidently possible for a memory controller to have a limit of 0 bytes, so it's possible for the oom killer to have a divide by zero error in such circumstances. When this is the case, each candidate task's rss and swap is divided by one so they are essentially ranked according to whichever task attached to the cgroup has the most resident RAM and swap. Signed-off-by: David Rientjes Reported-by: Greg Thelen Tested-by: Greg Thelen Acked-by: KAMEZAWA Hiroyuki Signed-off-by: Andrew Morton --- mm/oom_kill.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff -puN mm/oom_kill.c~oom-avoid-divide-by-zero mm/oom_kill.c --- a/mm/oom_kill.c~oom-avoid-divide-by-zero +++ a/mm/oom_kill.c @@ -175,6 +175,14 @@ unsigned int oom_badness(struct task_str p = find_lock_task_mm(p); if (!p) return 0; + + /* + * The memory controller can have a limit of 0 bytes, so avoid a divide + * by zero if necessary. + */ + if (!totalpages) + totalpages = 1; + /* * The baseline for the badness score is the proportion of RAM that each * task's rss and swap space use. _ Patches currently in -mm which might be from rientjes@google.com are origin.patch linux-next.patch hugetlbfs-kill-applications-that-use-map_noreserve-with-sigbus-instead-of-oom-killer.patch mempolicy-remove-redundant-code.patch oom-filter-tasks-not-sharing-the-same-cpuset.patch oom-sacrifice-child-with-highest-badness-score-for-parent.patch oom-select-task-from-tasklist-for-mempolicy-ooms.patch oom-remove-special-handling-for-pagefault-ooms.patch oom-badness-heuristic-rewrite.patch oom-deprecate-oom_adj-tunable.patch oom-replace-sysctls-with-quick-mode.patch oom-avoid-oom-killer-for-lowmem-allocations.patch oom-remove-unnecessary-code-and-cleanup.patch oom-default-to-killing-current-for-pagefault-ooms.patch oom-avoid-race-for-oom-killed-tasks-detaching-mm-prior-to-exit.patch oom-select_bad_process-check-pf_kthread-instead-of-mm-to-skip-kthreads.patch oom-select_bad_process-pf_exiting-check-should-take-mm-into-account.patch oom-introduce-find_lock_task_mm-to-fix-mm-false-positives.patch oom-oom_forkbomb_penalty-move-thread_group_cputime-out-of-task_lock.patch oom-hold-tasklist_lock-when-dumping-tasks.patch oom-give-current-access-to-memory-reserves-if-it-has-been-killed.patch oom-avoid-sending-exiting-tasks-a-sigkill.patch oom-clean-up-oom_kill_task.patch oom-clean-up-oom_badness.patch oom-select_bad_process-never-choose-tasks-with-badness-==-0.patch oom-avoid-divide-by-zero.patch mempolicy-remove-case-mpol_interleave-from-policy_zonelist.patch mempolicy-remove-redundant-check.patch mempolicy-dont-call-mpol_set_nodemask-when-no_context.patch mempolicy-lose-unnecessary-loop-variable-in-mpol_parse_str.patch mempolicy-rename-policy_types-and-cleanup-initialization.patch mempolicy-factor-mpol_shared_policy_init-return-paths.patch mempolicy-document-cpuset-interaction-with-tmpfs-mpol-mount-option.patch mm-default-to-node-zonelist-ordering-when-nodes-have-only-lowmem.patch oom-move-sysctl-declarations-to-oomh.patch memcg-oom-wakeup-filter.patch memcg-oom-wakeup-filter-update.patch memcg-oom-notifier.patch memcg-oom-notifier-update.patch memcg-oom-kill-disable-and-oom-status.patch memcg-oom-kill-disable-and-oom-status-update.patch numa-add-generic-percpu-var-numa_node_id-implementation.patch numa-x86_64-use-generic-percpu-var-numa_node_id-implementation.patch numa-ia64-use-generic-percpu-var-numa_node_id-implementation.patch numa-introduce-numa_mem_id-effective-local-memory-node-id.patch numa-ia64-support-numa_mem_id-for-memoryless-nodes.patch numa-slab-use-numa_mem_id-for-slab-local-memory-node.patch numa-in-kernel-profiling-use-cpu_to_mem-for-per-cpu-allocations.patch numa-update-documentation-vm-numa-add-memoryless-node-info.patch