mm, oom: fix and cleanup oom score calculations (61eafb00) · Commits · 戴 / test

The divide in p->signal->oom_score_adj * totalpages / 1000 within oom_badness() was causing an overflow of the signed long data type. This adds both the root bias and p->signal->oom_score_adj before doing the normalization which fixes the issue and also cleans up the calculation. Tested-by:

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

David Rientjes <rientjes@google.com> Cc: KOSAKI Motohiro <kosaki.motohiro@gmail.com> Signed-off-by:

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

Linus Torvalds <torvalds@linux-foundation.org>

mm/oom_kill.c

+7 −8

Original line number	Diff line number	Diff line
		@@ -184,6 +184,7 @@ unsigned long oom_badness(struct task_struct p, struct mem_cgroup memcg,
		const nodemask_t *nodemask, unsigned long totalpages)
		{
		long points;
		long adj;

		if (oom_unkillable_task(p, memcg, nodemask))
		return 0;
		@@ -192,7 +193,8 @@ unsigned long oom_badness(struct task_struct p, struct mem_cgroup memcg,
		if (!p)
		return 0;

		if (p->signal->oom_score_adj == OOM_SCORE_ADJ_MIN) {
		adj = p->signal->oom_score_adj;
		if (adj == OOM_SCORE_ADJ_MIN) {
		task_unlock(p);
		return 0;
		}
		@@ -210,14 +212,11 @@ unsigned long oom_badness(struct task_struct p, struct mem_cgroup memcg,
		* implementation used by LSMs.
		*/
		if (has_capability_noaudit(p, CAP_SYS_ADMIN))
		points -= 30 * totalpages / 1000;
		adj -= 30;

		/*
		* /proc/pid/oom_score_adj ranges from -1000 to +1000 such that it may
		* either completely disable oom killing or always prefer a certain
		* task.
		*/
		points += p->signal->oom_score_adj * totalpages / 1000;
		/* Normalize to oom_score_adj units */
		adj *= totalpages / 1000;
		points += adj;

		/*
		* Never return 0 for an eligible task regardless of the root bonus and

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