linux-kernel - Re: vfs: lockdep splat with prepare_bprm

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Fri, 15 Mar 2013 04:26:28 +0000
From:	Al Viro <viro@...IV.linux.org.uk>
To:	Sasha Levin <sasha.levin@...cle.com>
Cc:	Dave Jones <davej@...hat.com>, Oleg Nesterov <oleg@...hat.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	"Eric W. Biederman" <ebiederm@...ssion.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: vfs: lockdep splat with prepare_bprm_creds

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
mutex_lock_killable()...
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/