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Diffstat (limited to 'mm/oom_kill.c')
-rw-r--r--mm/oom_kill.c59
1 files changed, 40 insertions, 19 deletions
diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index 1ecc0bcaecc5..e4778285d8d1 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -377,13 +377,11 @@ static void dump_tasks(struct mem_cgroup *memcg, const nodemask_t *nodemask)
static void dump_header(struct oom_control *oc, struct task_struct *p,
struct mem_cgroup *memcg)
{
- task_lock(current);
pr_warning("%s invoked oom-killer: gfp_mask=0x%x, order=%d, "
"oom_score_adj=%hd\n",
current->comm, oc->gfp_mask, oc->order,
current->signal->oom_score_adj);
- cpuset_print_task_mems_allowed(current);
- task_unlock(current);
+ cpuset_print_current_mems_allowed();
dump_stack();
if (memcg)
mem_cgroup_print_oom_info(memcg, p);
@@ -476,6 +474,24 @@ void oom_killer_enable(void)
oom_killer_disabled = false;
}
+/*
+ * task->mm can be NULL if the task is the exited group leader. So to
+ * determine whether the task is using a particular mm, we examine all the
+ * task's threads: if one of those is using this mm then this task was also
+ * using it.
+ */
+static bool process_shares_mm(struct task_struct *p, struct mm_struct *mm)
+{
+ struct task_struct *t;
+
+ for_each_thread(p, t) {
+ struct mm_struct *t_mm = READ_ONCE(t->mm);
+ if (t_mm)
+ return t_mm == mm;
+ }
+ return false;
+}
+
#define K(x) ((x) << (PAGE_SHIFT-10))
/*
* Must be called while holding a reference to p, which will be released upon
@@ -509,10 +525,8 @@ void oom_kill_process(struct oom_control *oc, struct task_struct *p,
if (__ratelimit(&oom_rs))
dump_header(oc, p, memcg);
- task_lock(p);
pr_err("%s: Kill process %d (%s) score %u or sacrifice child\n",
message, task_pid_nr(p), p->comm, points);
- task_unlock(p);
/*
* If any of p's children has a different mm and is eligible for kill,
@@ -525,7 +539,7 @@ void oom_kill_process(struct oom_control *oc, struct task_struct *p,
list_for_each_entry(child, &t->children, sibling) {
unsigned int child_points;
- if (child->mm == p->mm)
+ if (process_shares_mm(child, p->mm))
continue;
/*
* oom_badness() returns 0 if the thread is unkillable
@@ -552,8 +566,15 @@ void oom_kill_process(struct oom_control *oc, struct task_struct *p,
victim = p;
}
- /* mm cannot safely be dereferenced after task_unlock(victim) */
+ /* Get a reference to safely compare mm after task_unlock(victim) */
mm = victim->mm;
+ atomic_inc(&mm->mm_count);
+ /*
+ * We should send SIGKILL before setting TIF_MEMDIE in order to prevent
+ * the OOM victim from depleting the memory reserves from the user
+ * space under its control.
+ */
+ do_send_sig_info(SIGKILL, SEND_SIG_FORCED, victim, true);
mark_oom_victim(victim);
pr_err("Killed process %d (%s) total-vm:%lukB, anon-rss:%lukB, file-rss:%lukB\n",
task_pid_nr(victim), victim->comm, K(victim->mm->total_vm),
@@ -571,21 +592,21 @@ void oom_kill_process(struct oom_control *oc, struct task_struct *p,
* pending fatal signal.
*/
rcu_read_lock();
- for_each_process(p)
- if (p->mm == mm && !same_thread_group(p, victim) &&
- !(p->flags & PF_KTHREAD)) {
- if (p->signal->oom_score_adj == OOM_SCORE_ADJ_MIN)
- continue;
+ for_each_process(p) {
+ if (!process_shares_mm(p, mm))
+ continue;
+ if (same_thread_group(p, victim))
+ continue;
+ if (unlikely(p->flags & PF_KTHREAD))
+ continue;
+ if (p->signal->oom_score_adj == OOM_SCORE_ADJ_MIN)
+ continue;
- task_lock(p); /* Protect ->comm from prctl() */
- pr_err("Kill process %d (%s) sharing same memory\n",
- task_pid_nr(p), p->comm);
- task_unlock(p);
- do_send_sig_info(SIGKILL, SEND_SIG_FORCED, p, true);
- }
+ do_send_sig_info(SIGKILL, SEND_SIG_FORCED, p, true);
+ }
rcu_read_unlock();
- do_send_sig_info(SIGKILL, SEND_SIG_FORCED, victim, true);
+ mmdrop(mm);
put_task_struct(victim);
}
#undef K