linux-kernel - Re: Possible deadlock in videobuf_dma_init

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] [day] [month] [year] [list]

Message-Id: <1156103415.23756.58.camel@laptopd505.fenrus.org>
Date:	Sun, 20 Aug 2006 21:50:15 +0200
From:	Arjan van de Ven <arjan@...radead.org>
To:	Petr Vandrovec <petr@...drovec.name>
Cc:	video4linux-list@...hat.com, linux-kernel@...r.kernel.org
Subject: Re: Possible deadlock in videobuf_dma_init_user

On Sun, 2006-08-20 at 21:19 +0200, Petr Vandrovec wrote:
> Hello,
>   my kernel is a bit unhappy with lock ordering between mm->mmap_sem 
> and videobuf_queue->lock.
> 					Thanks,
> 						Petr Vandrovec


looks like a real deadlock to me...

bttv_prepare_buffer takes mutex then
videobuf_dma_init_user takes mmap_sem



do_mmap_pgoff takes mmap_sem then calls
bttv_mmap which calls
videobuf_mmap_mapper takes the mutex


so a classic AB-BA deadlock....


-
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/