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@xxxxxxxxxx>
Signed-off-by: David Rientjes <rientjes@xxxxxxxxxx>
---
mm/oom_kill.c | 15 +++++++--------
1 file changed, 7 insertions(+), 8 deletions(-)
diff --git a/mm/oom_kill.c b/mm/oom_kill.c
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -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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