Messages in this thread Patch in this message | | | Date | Tue, 27 Dec 2011 09:35:59 -0800 | From | Tejun Heo <> | Subject | [PATCH block/for-3.3/core] block: remove WARN_ON_ONCE() in exit_io_context() |
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6e736be7 "block: make ioc get/put interface more conventional and fix race on alloction" added WARN_ON_ONCE() in exit_io_context() which triggers if !PF_EXITING. All tasks hitting exit_io_context() from task exit should have PF_EXITING set but task struct tearing down after fork failure calls into the function without PF_EXITING, triggering the condition.
WARNING: at block/blk-ioc.c:234 exit_io_context+0x40/0x92() Pid: 17090, comm: trinity Not tainted 3.2.0-rc6-next-20111222-sasha-dirty #77 Call Trace: [<ffffffff810b69a3>] warn_slowpath_common+0x8f/0xb2 [<ffffffff810b6a77>] warn_slowpath_null+0x18/0x1a [<ffffffff8181a7a2>] exit_io_context+0x40/0x92 [<ffffffff810b58c9>] copy_process+0x126f/0x1453 [<ffffffff810b5c1b>] do_fork+0x120/0x3e9 [<ffffffff8106242f>] sys_clone+0x26/0x28 [<ffffffff82425803>] stub_clone+0x13/0x20 ---[ end trace a2e4eb670b375238 ]---
Reported-by: Sasha Levin <levinsasha928@gmail.com> Signed-off-by: Tejun Heo <tj@kernel.org> --- Heh, sorry about that. Forgot about fork failure path. Just removing the WARN_ON_ONCE() should be enough. Thanks for reporting the problem.
block/blk-ioc.c | 3 --- 1 file changed, 3 deletions(-)
diff --git a/block/blk-ioc.c b/block/blk-ioc.c index 33fae7d..27a06e0 100644 --- a/block/blk-ioc.c +++ b/block/blk-ioc.c @@ -230,9 +230,6 @@ void exit_io_context(struct task_struct *task) { struct io_context *ioc; - /* PF_EXITING prevents new io_context from being attached to @task */ - WARN_ON_ONCE(!(current->flags & PF_EXITING)); - task_lock(task); ioc = task->io_context; task->io_context = NULL;
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