Re: mq: INFO: possible circular locking dependency detected

2012-08-14 Thread Jan Kara
On Tue 14-08-12 23:13:31, Al Viro wrote: > On Wed, Aug 15, 2012 at 12:09:27AM +0200, Jan Kara wrote: > > OK, this is a theoretical deadlock since mqueue (virtual) filesystem > > cannot > > really be frozen. But we should convert the mqueue code to deal with new > > lock ordering of i_mutex and m

Re: mq: INFO: possible circular locking dependency detected

2012-08-14 Thread Al Viro
On Wed, Aug 15, 2012 at 12:09:27AM +0200, Jan Kara wrote: > OK, this is a theoretical deadlock since mqueue (virtual) filesystem cannot > really be frozen. But we should convert the mqueue code to deal with new > lock ordering of i_mutex and mnt_want_write() anyway to make lockdep happy > if anyt

Re: mq: INFO: possible circular locking dependency detected

2012-08-14 Thread Jan Kara
On Wed 08-08-12 15:54:39, Wu Fengguang wrote: > On Wed, Aug 08, 2012 at 03:17:38PM +0800, Fengguang Wu wrote: > > On Tue, Aug 07, 2012 at 07:39:55AM +0100, Al Viro wrote: > > > On Tue, Aug 07, 2012 at 01:04:12PM +0800, Fengguang Wu wrote: > > > > > > > FYI, here is a different back trace on that c

Re: mq: INFO: possible circular locking dependency detected

2012-08-08 Thread Fengguang Wu
On Tue, Aug 07, 2012 at 04:54:44PM +0200, Sasha Levin wrote: > On 08/06/2012 08:34 AM, Al Viro wrote: > > On Sat, Aug 04, 2012 at 12:59:31PM +0200, Sasha Levin wrote: > >> Hi all, > >> > >> While fuzzing with trinity inside a KVM tools guest, using latest -next > >> kernel, I've stumbled on the du

Re: mq: INFO: possible circular locking dependency detected

2012-08-08 Thread Fengguang Wu
On Tue, Aug 07, 2012 at 07:39:55AM +0100, Al Viro wrote: > On Tue, Aug 07, 2012 at 01:04:12PM +0800, Fengguang Wu wrote: > > > FYI, here is a different back trace on that commit. > > > > [3.255043] == > > [3.255052] [ INFO: possible circ

Re: mq: INFO: possible circular locking dependency detected

2012-08-07 Thread Sasha Levin
On 08/06/2012 08:34 AM, Al Viro wrote: > On Sat, Aug 04, 2012 at 12:59:31PM +0200, Sasha Levin wrote: >> Hi all, >> >> While fuzzing with trinity inside a KVM tools guest, using latest -next >> kernel, I've stumbled on the dump below. >> >> I think this is the result of commit 765927b2 ("switch de

Re: mq: INFO: possible circular locking dependency detected

2012-08-06 Thread Al Viro
On Tue, Aug 07, 2012 at 01:04:12PM +0800, Fengguang Wu wrote: > FYI, here is a different back trace on that commit. > > [3.255043] == > [3.255052] [ INFO: possible circular locking dependency detected ] > [3.255052] 3.5.0-rc6-bisect-

Re: mq: INFO: possible circular locking dependency detected

2012-08-05 Thread Al Viro
On Sat, Aug 04, 2012 at 12:59:31PM +0200, Sasha Levin wrote: > Hi all, > > While fuzzing with trinity inside a KVM tools guest, using latest -next > kernel, I've stumbled on the dump below. > > I think this is the result of commit 765927b2 ("switch dentry_open() to > struct path, make it grab r