linux-kernel - Re: [RFC][PATCH] EXT3: problem with page fault inside a transaction

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 for Android: free password hash cracker in your pocket

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

Message-Id: <20061011234330.efae4265.akpm@osdl.org>
Date:	Wed, 11 Oct 2006 23:43:30 -0700
From:	Andrew Morton <akpm@...l.org>
To:	Dmitriy Monakhov <dmonakhov@...nvz.org>
Cc:	Linux Kernel <linux-kernel@...r.kernel.org>,
	Linux Memory Management <linux-mm@...ck.org>,
	<devel@...nvz.org>, ext2-devel@...ts.sourceforge.net,
	Andrey Savochkin <saw@...oft.com>
Subject: Re: [RFC][PATCH] EXT3: problem with page fault inside a transaction

On Thu, 12 Oct 2006 09:57:26 +0400
Dmitriy Monakhov <dmonakhov@...nvz.org> wrote:

> While reading Andrew's generic_file_buffered_write patches i've remembered
> one more EXT3 issue.journal_start() in prepare_write() causes different ranking
> violations if copy_from_user() triggers a page fault. It could cause 
> GFP_FS allocation, re-entering into ext3 code possibly with a different
> superblock and journal, ranking violation of journalling serialization 
> and mmap_sem and page lock and all other kinds of funny consequences.

With the stuff Nick and I are looking at, we won't take pagefaults inside
prepare_write()/commit_write() any more.

> Our customers complain about this issue.

Really?  How often?

What on earth are they doing to trigger this?  writev() without the 2.6.18
writev() bugfix?
-
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/