+ oom-avoid-divide-by-zero.patch added to -mm tree

[akpm@linux-foundation.org]

The patch titled
     oom: avoid divide by zero
has been added to the -mm tree.  Its filename is
     oom-avoid-divide-by-zero.patch

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------------------------------------------------------
Subject: oom: avoid divide by zero
From: David Rientjes <rientjes@google.com>

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 <rientjes@google.com>
Reported-by: Greg Thelen <gthelen@google.com>
Tested-by: Greg Thelen <gthelen@google.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 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