linux-kernel - Re: [PATCH] get_user_pages(..., write==1, ...) may return with readable pte.

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]

Date:	Sun, 15 Oct 2006 10:03:51 +0200
From:	Nick Piggin <npiggin@...e.de>
To:	Robin Holt <holt@....com>
Cc:	Hugh Dickins <hugh@...itas.com>,
	Linus Torvalds <torvalds@...l.org>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] get_user_pages(..., write==1, ...) may return with readable pte.

On Sat, Oct 14, 2006 at 05:15:07AM -0500, Robin Holt wrote:
> > dup_mmap holds mmap_sem for write. get_user_pages caller must hold it
> > for read.
> 
> I could have sworn I checked for that and found a down_read(), but
> now that I look when I have some time, it is clearly a down_write().
> Sorry for the distraction.

I'm one to do the same thing, don't worry ;)

> It is a user job that is passing data between hosts.  The host is
> under heavy memory pressure and one rank of the MPI job gets silent
> data corruption.

http://www.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=016eb4a0ed06a3677d67a584da901f0e9a63c666

It could be this? inode reclaim calls invalidate_inode_pages, so this
one is a memory corrupter under heavy reclaim pressure.


> 
> Thanks and sorry for wasting your time,

Not at all, my pleasure.
-
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/