| From 412d32e6c98527078779e5b515823b2810e40324 Mon Sep 17 00:00:00 2001 |
| From: Mike Galbraith <mgalbraith@suse.de> |
| Date: Wed, 28 Nov 2012 07:17:18 +0100 |
| Subject: workqueue: exit rescuer_thread() as TASK_RUNNING |
| |
| From: Mike Galbraith <mgalbraith@suse.de> |
| |
| commit 412d32e6c98527078779e5b515823b2810e40324 upstream. |
| |
| A rescue thread exiting TASK_INTERRUPTIBLE can lead to a task scheduling |
| off, never to be seen again. In the case where this occurred, an exiting |
| thread hit reiserfs homebrew conditional resched while holding a mutex, |
| bringing the box to its knees. |
| |
| PID: 18105 TASK: ffff8807fd412180 CPU: 5 COMMAND: "kdmflush" |
| #0 [ffff8808157e7670] schedule at ffffffff8143f489 |
| #1 [ffff8808157e77b8] reiserfs_get_block at ffffffffa038ab2d [reiserfs] |
| #2 [ffff8808157e79a8] __block_write_begin at ffffffff8117fb14 |
| #3 [ffff8808157e7a98] reiserfs_write_begin at ffffffffa0388695 [reiserfs] |
| #4 [ffff8808157e7ad8] generic_perform_write at ffffffff810ee9e2 |
| #5 [ffff8808157e7b58] generic_file_buffered_write at ffffffff810eeb41 |
| #6 [ffff8808157e7ba8] __generic_file_aio_write at ffffffff810f1a3a |
| #7 [ffff8808157e7c58] generic_file_aio_write at ffffffff810f1c88 |
| #8 [ffff8808157e7cc8] do_sync_write at ffffffff8114f850 |
| #9 [ffff8808157e7dd8] do_acct_process at ffffffff810a268f |
| [exception RIP: kernel_thread_helper] |
| RIP: ffffffff8144a5c0 RSP: ffff8808157e7f58 RFLAGS: 00000202 |
| RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 |
| RDX: 0000000000000000 RSI: ffffffff8107af60 RDI: ffff8803ee491d18 |
| RBP: 0000000000000000 R8: 0000000000000000 R9: 0000000000000000 |
| R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 |
| R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 |
| ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018 |
| |
| Signed-off-by: Mike Galbraith <mgalbraith@suse.de> |
| Signed-off-by: Tejun Heo <tj@kernel.org> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| kernel/workqueue.c | 4 +++- |
| 1 file changed, 3 insertions(+), 1 deletion(-) |
| |
| --- a/kernel/workqueue.c |
| +++ b/kernel/workqueue.c |
| @@ -2266,8 +2266,10 @@ static int rescuer_thread(void *__wq) |
| repeat: |
| set_current_state(TASK_INTERRUPTIBLE); |
| |
| - if (kthread_should_stop()) |
| + if (kthread_should_stop()) { |
| + __set_current_state(TASK_RUNNING); |
| return 0; |
| + } |
| |
| /* |
| * See whether any cpu is asking for help. Unbounded |
