linux-kernel - Re: [BUG] drivers/video/sis: deadlock introduced by "fbdev: add mutex for fb

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: <20090705150134.GB8326@linux-sh.org>
Date:	Mon, 6 Jul 2009 00:01:35 +0900
From:	Paul Mundt <lethal@...ux-sh.org>
To:	Linus Torvalds <torvalds@...ux-foundation.org>
Cc:	Wu Zhangjin <wuzhangjin@...il.com>, linux-media@...r.kernel.org,
	linux-kernel@...r.kernel.org, linux-mips@...ux-mips.org,
	Krzysztof Helt <krzysztof.h1@...pl>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	"Rafael J. Wysocki" <rjw@...k.pl>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Ralf Baechle <ralf@...ux-mips.org>, ???? <yanh@...ote.com>,
	zhangfx <zhangfx@...ote.com>
Subject: Re: [BUG] drivers/video/sis: deadlock introduced by "fbdev: add mutex for fb_mmap locking"

On Sun, Jul 05, 2009 at 07:56:56AM -0700, Linus Torvalds wrote:
> 
> 
> On Sun, 5 Jul 2009, Paul Mundt wrote:
> >  			break;
> >  	fb_info->node = i;
> >  	mutex_init(&fb_info->lock);
> > -	mutex_init(&fb_info->mm_lock);
> 
> Why not "lock" as well?
> 
I had that initially, but matroxfb will break if we do that, and
presently nothing cares about trying to take ->lock that early on.

->mm_lock was a special case as the lock/unlock pairs were sprinkled
around well before initialization, while in the ->lock case all of the
lock/unlock pairs are handled internally by the fbmem code (at least a
quick grep does not show any drivers using it on their own).
--
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/