mm, oom: fix badness score underflow (1e11ad8d) · Commits · 戴 / test

If the privileges given to root threads (3% of allowable memory) or a negative value of /proc/pid/oom_score_adj happen to exceed the amount of rss of a thread, its badness score overflows as a result of commit ("mm, oom: normalize oom scores to oom_score_adj scale only for userspace"). Fix this by making the type signed and return 1, meaning the thread is still eligible for kill, if the value is negative. Reported-by:

Dave Jones <davej@redhat.com> Acked-by:

Oleg Nesterov <oleg@redhat.com> Signed-off-by:

David Rientjes <rientjes@google.com> Signed-off-by:

Linus Torvalds <torvalds@linux-foundation.org>

mm/oom_kill.c

+2 −2

Original line number	Original line	Diff line number	Diff line
	@@ -183,7 +183,7 @@ static bool oom_unkillable_task(struct task_struct *p,
	unsigned long oom_badness(struct task_struct p, struct mem_cgroup memcg,		unsigned long oom_badness(struct task_struct p, struct mem_cgroup memcg,
	const nodemask_t *nodemask, unsigned long totalpages)		const nodemask_t *nodemask, unsigned long totalpages)
	{		{
	unsigned long points;		long points;

	if (oom_unkillable_task(p, memcg, nodemask))		if (oom_unkillable_task(p, memcg, nodemask))
	return 0;		return 0;
	@@ -223,7 +223,7 @@ unsigned long oom_badness(struct task_struct p, struct mem_cgroup memcg,
	* Never return 0 for an eligible task regardless of the root bonus and		* Never return 0 for an eligible task regardless of the root bonus and
	* oom_score_adj (oom_score_adj can't be OOM_SCORE_ADJ_MIN here).		* oom_score_adj (oom_score_adj can't be OOM_SCORE_ADJ_MIN here).
	*/		*/
	return points ? points : 1;		return points > 0 ? points : 1;
	}		}

	/*		/*

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