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: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index 7dcca55..b19c78e 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -458,10 +458,10 @@
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 @@
* 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
*/