mm, oom: fix a comment in dump_task()

If p is a kthread, it will be checked in oom_unkillable_task() so
we can delete the corresponding comment.

Link: https://lkml.kernel.org/r/20210125133006.7242-1-tangyizhou@huawei.com
Signed-off-by: Tang Yizhou <tangyizhou@huawei.com>
Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/oom_kill.c

@@ -395,9 +395,8 @@ static int dump_task(struct task_struct *p, void *arg)
 	task = find_lock_task_mm(p);
 	if (!task) {
 		/*
-		 * This is a kthread or all of p's threads have already
-		 * detached their mm's.  There's no need to report
-		 * them; they can't be oom killed anyway.
+		 * All of p's threads have already detached their mm's. There's
+		 * no need to report them; they can't be oom killed anyway.
 		 */
 		return 0;
 	}