Commit 61eafb00 authored by David Rientjes's avatar David Rientjes Committed by Linus Torvalds

mm, oom: fix and cleanup oom score calculations

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: default avatarDave Jones <davej@redhat.com>
Signed-off-by: default avatarDavid Rientjes <rientjes@google.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@gmail.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent fbb24a3a
...@@ -184,6 +184,7 @@ unsigned long oom_badness(struct task_struct *p, struct mem_cgroup *memcg, ...@@ -184,6 +184,7 @@ 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)
{ {
long points; long points;
long adj;
if (oom_unkillable_task(p, memcg, nodemask)) if (oom_unkillable_task(p, memcg, nodemask))
return 0; return 0;
...@@ -192,7 +193,8 @@ unsigned long oom_badness(struct task_struct *p, struct mem_cgroup *memcg, ...@@ -192,7 +193,8 @@ unsigned long oom_badness(struct task_struct *p, struct mem_cgroup *memcg,
if (!p) if (!p)
return 0; 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); task_unlock(p);
return 0; return 0;
} }
...@@ -210,14 +212,11 @@ unsigned long oom_badness(struct task_struct *p, struct mem_cgroup *memcg, ...@@ -210,14 +212,11 @@ unsigned long oom_badness(struct task_struct *p, struct mem_cgroup *memcg,
* implementation used by LSMs. * implementation used by LSMs.
*/ */
if (has_capability_noaudit(p, CAP_SYS_ADMIN)) if (has_capability_noaudit(p, CAP_SYS_ADMIN))
points -= 30 * totalpages / 1000; adj -= 30;
/* /* Normalize to oom_score_adj units */
* /proc/pid/oom_score_adj ranges from -1000 to +1000 such that it may adj *= totalpages / 1000;
* either completely disable oom killing or always prefer a certain points += adj;
* task.
*/
points += p->signal->oom_score_adj * totalpages / 1000;
/* /*
* 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
......
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