Re: vfs: lockdep splat with prepare_bprm_creds

From: Al Viro
Date: Fri Mar 15 2013 - 00:26:52 EST

On Fri, Mar 15, 2013 at 12:07:14AM -0400, Sasha Levin wrote:
> Hi all,
> While fuzzing with trinity inside a KVM tools guest running latest -next kernel
> I've stumbled on the following.
> Dave Jones reported something similar, but that seemed to involve cgroup's mutex
> and didn't seem like it was the same issue as this one.

Lovely... It's an execve() attempt on a "binary" that is, in fact, a procfs
file (/proc/<pid>/stack), with its ->read() trying to grab ->cred_guard_mutex.
The fact that it's seq_file-based is irrelevant here - all that matters is
that we have ->read() for some file trying to grab ->cred_guard_mutex.

It's not *quite* a deadlock, though - all these guys are using
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