Re: mq: INFO: possible circular locking dependency detected

From: Fengguang Wu
Date: Wed Aug 08 2012 - 03:17:58 EST


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 circular locking dependency detected ]
> > [ 3.255052] 3.5.0-rc6-bisect-00355-geb04c28 #4 Not tainted
> > [ 3.255052] -------------------------------------------------------
> > [ 3.255052] init/1 is trying to acquire lock:
> > [ 3.255052] (&mm->mmap_sem){++++++}, at: [<ffffffff81180d00>] might_fault+0x70/0xe0
> > [ 3.255052]
> > [ 3.255052] but task is already holding lock:
> > [ 3.255052] (&sb->s_type->i_mutex_key){+.+.+.}, at: [<ffffffff811d191e>] vfs_readdir+0x6e/0x130
>
> Do you see any similar with the _next_ commit?

Stress tests show that the next commit is free from both the "circular
locking dependency" issues.

Thanks,
Fengguang
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