2013-03-22 10:44:06

by Sergey Senozhatsky

Subject: [-next] fs/eventpoll.c:545 suspicious rcu_dereference_check() usage

Hello,

got this with today's linux-next

[ 3.163894] ===============================
[ 3.163895] [ INFO: suspicious RCU usage. ]
[ 3.163897] 3.9.0-rc3-next-20130322-dbg-dirty #1 Not tainted
[ 3.163898] -------------------------------
[ 3.163900] fs/eventpoll.c:545 suspicious rcu_dereference_check() usage!
[ 3.163900] other info that might help us debug this:
[ 3.163902] rcu_scheduler_active = 1, debug_locks = 1
[ 3.163903] 2 locks held by ata_id/763:
[ 3.163915] #0: (&pipe->wait){......}, at: [<ffffffff810757a7>] __wake_up_sync_key+0x37/0x80
[ 3.163923] #1: (&(&ep->lock)->rlock){......}, at: [<ffffffff811bb4a9>] ep_poll_callback+0x59/0x1f0
[ 3.163924] stack backtrace:
[ 3.163927] Pid: 763, comm: ata_id Not tainted 3.9.0-rc3-next-20130322-dbg-dirty #1
[ 3.163929] Call Trace:
[ 3.163940] [<ffffffff810a7c66>] lockdep_rcu_suspicious+0xe6/0x130
[ 3.163945] [<ffffffff811bb61f>] ep_poll_callback+0x1cf/0x1f0
[ 3.163949] [<ffffffff81074765>] __wake_up_common+0x55/0x90
[ 3.163952] [<ffffffff810757c3>] __wake_up_sync_key+0x53/0x80
[ 3.163957] [<ffffffff811775f8>] pipe_write+0x448/0x590
[ 3.163962] [<ffffffff8116df70>] do_sync_write+0x80/0xb0
[ 3.163965] [<ffffffff8116e938>] vfs_write+0xa8/0x180
[ 3.163968] [<ffffffff8116ec95>] SyS_write+0x55/0xb0
[ 3.163975] [<ffffffff81620506>] system_call_fastpath+0x1a/0x1f



-ss

2013-03-23 17:34:23

by Eric Wong

Subject: Re: [-next] fs/eventpoll.c:545 suspicious rcu_dereference_check() usage

Sergey Senozhatsky <[email protected]> wrote:
> [ 3.163894] ===============================
> [ 3.163895] [ INFO: suspicious RCU usage. ]
> [ 3.163897] 3.9.0-rc3-next-20130322-dbg-dirty #1 Not tainted
> [ 3.163898] -------------------------------
> [ 3.163900] fs/eventpoll.c:545 suspicious rcu_dereference_check() usage!

Sorry about this, I've fixed this and it is in the latest -mm

http://mid.gmane.org/[email protected]

2013-03-24 08:41:56

by Sergey Senozhatsky

Subject: Re: [-next] fs/eventpoll.c:545 suspicious rcu_dereference_check() usage

On (03/23/13 17:34), Eric Wong wrote:
> Sergey Senozhatsky <[email protected]> wrote:
> > [ 3.163894] ===============================
> > [ 3.163895] [ INFO: suspicious RCU usage. ]
> > [ 3.163897] 3.9.0-rc3-next-20130322-dbg-dirty #1 Not tainted
> > [ 3.163898] -------------------------------
> > [ 3.163900] fs/eventpoll.c:545 suspicious rcu_dereference_check() usage!
>
> Sorry about this, I've fixed this and it is in the latest -mm
>
> http://mid.gmane.org/[email protected]
>

thanks a lot.

-ss