From: Al Viro <viro@ZenIV.linux.org.uk>
To: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Sasha Levin <sasha.levin@oracle.com>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
Dave Jones <davej@redhat.com>
Subject: Re: fs: lockup on rename_mutex in fs/dcache.c:1035
Date: Sun, 26 Oct 2014 03:06:08 +0000 [thread overview]
Message-ID: <20141026030608.GN7996@ZenIV.linux.org.uk> (raw)
In-Reply-To: <87siibttyi.fsf@x220.int.ebiederm.org>
On Sat, Oct 25, 2014 at 08:01:41PM -0700, Eric W. Biederman wrote:
> Sasha Levin <sasha.levin@oracle.com> writes:
>
> > Hi all,
> >
> > While fuzzing with trinity inside a KVM tools guest running the latest -next
> > kernel, I've stumbled on the following spew:
>
> Weird. I took a quick look and I don't see any changes in d_walk that
> in Al's tree or in Linus's kernel for years.
>
> Has read_seqbegin_or_lock changed somewhere?
>
> >From a quick reading of the code it simply isn't possible for d_walk to
> take the lock twice short of memory corruption. And the fact that the
> code has not changed in years seems to suggest it isn't the obvious
> cause of d_walk talking the rename_lock twice.
It is a fairly obvious case of d_walk() forgetting to drop rename_lock.
See upthread for analysis and (hopefully) a fix.
next prev parent reply other threads:[~2014-10-26 3:06 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-26 1:39 fs: lockup on rename_mutex in fs/dcache.c:1035 Sasha Levin
2014-10-26 2:56 ` Al Viro
2014-10-26 3:01 ` Eric W. Biederman
2014-10-26 3:06 ` Al Viro [this message]
2014-10-26 3:51 ` Al Viro
2014-10-26 3:57 ` Al Viro
2014-10-26 18:56 ` Linus Torvalds
2014-10-26 19:13 ` Al Viro
2014-10-26 21:57 ` Al Viro
2014-10-26 23:33 ` Linus Torvalds
2014-10-26 23:42 ` Al Viro
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