Commit dc1b83ab authored by Oleg Nesterov's avatar Oleg Nesterov Committed by Linus Torvalds

oom: oom_kill_process: fix the child_points logic

oom_kill_process() starts with victim_points == 0.  This means that
(most likely) any child has more points and can be killed erroneously.

Also, "children has a different mm" doesn't match the reality, we should
check child->mm != t->mm.  This check is not exactly correct if t->mm ==
NULL but this doesn't really matter, oom_kill_task() will kill them
anyway.

Note: "Kill all processes sharing p->mm" in oom_kill_task() is wrong
too.
Signed-off-by: default avatarOleg Nesterov <oleg@redhat.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 5f40d420
...@@ -458,10 +458,10 @@ static int oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order, ...@@ -458,10 +458,10 @@ static int oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order,
struct mem_cgroup *mem, nodemask_t *nodemask, struct mem_cgroup *mem, nodemask_t *nodemask,
const char *message) const char *message)
{ {
struct task_struct *victim = p; struct task_struct *victim;
struct task_struct *child; struct task_struct *child;
struct task_struct *t = p; struct task_struct *t;
unsigned int victim_points = 0; unsigned int victim_points;
if (printk_ratelimit()) if (printk_ratelimit())
dump_header(p, gfp_mask, order, mem, nodemask); dump_header(p, gfp_mask, order, mem, nodemask);
...@@ -487,10 +487,15 @@ static int oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order, ...@@ -487,10 +487,15 @@ static int oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order,
* parent. This attempts to lose the minimal amount of work done while * parent. This attempts to lose the minimal amount of work done while
* still freeing memory. * still freeing memory.
*/ */
victim_points = oom_badness(p, mem, nodemask, totalpages);
victim = p;
t = p;
do { do {
list_for_each_entry(child, &t->children, sibling) { list_for_each_entry(child, &t->children, sibling) {
unsigned int child_points; unsigned int child_points;
if (child->mm == t->mm)
continue;
/* /*
* oom_badness() returns 0 if the thread is unkillable * oom_badness() returns 0 if the thread is unkillable
*/ */
......
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