task_work: add a scheduling point in task_work_run()

It seems commit 4a9d4b024a31 ("switch fput to task_work_add") re-
introduced the problem addressed in 944be0b22472 ("close_files(): add
scheduling point")

If a server process with a lot of files (say 2 million tcp sockets) is
killed, we can spend a lot of time in task_work_run() and trigger a soft
lockup.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/kernel/task_work.c b/kernel/task_work.c
index 91d4e1742a0c4ec1cd8805b6663f5a95b5d42b3b..d320d44903bd0ab8ce3a1dc3e40dee28a26e714f 100644 (file)
--- a/kernel/task_work.c
+++ b/kernel/task_work.c
@@ -75,6 +75,7 @@ void task_work_run(void)
                        p = q->next;
                        q->func(q);
                        q = p;
+                       cond_resched();
                }
        }
 }