oom, oom_reaper: disable oom_reaper for oom_kill_allocating_task (855b0183) · Commits · 戴 / test

Tetsuo has reported that oom_kill_allocating_task=1 will cause oom_reaper_list corruption because oom_kill_process doesn't follow standard OOM exclusion (aka ignores TIF_MEMDIE) and allows to enqueue the same task multiple times - e.g. by sacrificing the same child multiple times. This patch fixes the issue by introducing a new MMF_OOM_KILLED mm flag which is set in oom_kill_process atomically and oom reaper is disabled if the flag was already set. Signed-off-by:

Michal Hocko <mhocko@suse.com> Reported-by:

Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: David Rientjes <rientjes@google.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by:

Andrew Morton <akpm@linux-foundation.org> Signed-off-by:

Linus Torvalds <torvalds@linux-foundation.org>

include/linux/sched.h

+2 −0

Original line number	Diff line number	Diff line
		@@ -512,6 +512,8 @@ static inline int get_dumpable(struct mm_struct *mm)
		#define MMF_HAS_UPROBES 19 /* has uprobes */
		#define MMF_RECALC_UPROBES 20 /* MMF_HAS_UPROBES can be wrong */

		#define MMF_OOM_KILLED 21 /* OOM killer has chosen this mm */

		#define MMF_INIT_MASK (MMF_DUMPABLE_MASK \| MMF_DUMP_FILTER_MASK)

		struct sighand_struct {

mm/oom_kill.c

+5 −1

Original line number	Diff line number	Diff line
		@@ -680,7 +680,7 @@ void oom_kill_process(struct oom_control oc, struct task_struct p,
		unsigned int victim_points = 0;
		static DEFINE_RATELIMIT_STATE(oom_rs, DEFAULT_RATELIMIT_INTERVAL,
		DEFAULT_RATELIMIT_BURST);
		bool can_oom_reap = true;
		bool can_oom_reap;

		/*
		* If the task is already exiting, don't alarm the sysadmin or kill
		@@ -742,6 +742,10 @@ void oom_kill_process(struct oom_control oc, struct task_struct p,
		/* Get a reference to safely compare mm after task_unlock(victim) */
		mm = victim->mm;
		atomic_inc(&mm->mm_count);

		/* Make sure we do not try to oom reap the mm multiple times */
		can_oom_reap = !test_and_set_bit(MMF_OOM_KILLED, &mm->flags);

		/*
		* We should send SIGKILL before setting TIF_MEMDIE in order to prevent
		* the OOM victim from depleting the memory reserves from the user

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