Merge tag 'v4.4.177' into toradex_vf_4.4-nextColibri-VF_LXDE-Image_2.8b6.183-20190331

This is the 4.4.177 stable release

1 files changed, 8 insertions, 0 deletions

diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index c12680993ff3..bc781cdc0d04 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -544,6 +544,13 @@ void oom_kill_process(struct oom_control *oc, struct task_struct *p,
 	 * still freeing memory.
 	 */
 	read_lock(&tasklist_lock);
+
+	/*
+	 * The task 'p' might have already exited before reaching here. The
+	 * put_task_struct() will free task_struct 'p' while the loop still try
+	 * to access the field of 'p', so, get an extra reference.
+	 */
+	get_task_struct(p);
 	for_each_thread(p, t) {
 		list_for_each_entry(child, &t->children, sibling) {
 			unsigned int child_points;
@@ -563,6 +570,7 @@ void oom_kill_process(struct oom_control *oc, struct task_struct *p,
 			}
 		}
 	}
+	put_task_struct(p);
 	read_unlock(&tasklist_lock);
 
 	p = find_lock_task_mm(victim);