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

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

mm/oom_kill.c

+8 −3
Original line number Diff line number Diff line
@@ -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,

			    const char *message)

{

	struct task_struct *victim = p;

	struct task_struct *victim;

	struct task_struct *child;

	struct task_struct *t = p;

	unsigned int victim_points = 0;

	struct task_struct *t;

	unsigned int victim_points;



	if (printk_ratelimit())

		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, 
	 * parent.  This attempts to lose the minimal amount of work done while

	 * still freeing memory.

	 */

	victim_points = oom_badness(p, mem, nodemask, totalpages);

	victim = p;

	t = p;

	do {

		list_for_each_entry(child, &t->children, sibling) {

			unsigned int child_points;



			if (child->mm == t->mm)

				continue;

			/*

			 * oom_badness() returns 0 if the thread is unkillable

			 */