linux-kernel - Re: 3.14-rc2 XFS backtrace because irqs

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]

Message-ID: <20140215152251.GY18016@ZenIV.linux.org.uk>
Date:	Sat, 15 Feb 2014 15:22:51 +0000
From:	Al Viro <viro@...IV.linux.org.uk>
To:	Oleg Nesterov <oleg@...hat.com>
Cc:	Linus Torvalds <torvalds@...ux-foundation.org>,
	Dave Chinner <david@...morbit.com>,
	Dave Jones <davej@...hat.com>,
	Eric Sandeen <sandeen@...deen.net>,
	Linux Kernel <linux-kernel@...r.kernel.org>, xfs@....sgi.com
Subject: Re: 3.14-rc2 XFS backtrace because irqs_disabled.

On Sat, Feb 15, 2014 at 03:27:00PM +0100, Oleg Nesterov wrote:

> 1. info->q can be already freed if SIGQUEUE_PREALLOC.
> 
>    Once get_signal_to_deliver() or any other caller drops ->siglock
>    another thread can do sys_timer_delete()->sigqueue_free().

How the devil would it find the sucker?  It's off the list already.

> 2. We need to move do_schedule_next_timer() from dequeue_signal()
>    here.
> 
>    Otherwise ->q can be reused/overwritten by the next send_sigqueue()
>    right affter ->siglock is dropped.

Ditto.  We rip them out of queue on collect_signal(); the only thing we do
not do is actual __sigqueue_free().
--
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/