linux-kernel - Re: Revert "aio: fix aio request leak when events are reaped by user space"

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: <20140819171426.GA11811@gmail.com>
Date:	Tue, 19 Aug 2014 20:14:26 +0300
From:	Dan Aloni <dan@...nelim.com>
To:	Benjamin LaHaise <bcrl@...ck.org>
Cc:	Linus Torvalds <torvalds@...ux-foundation.org>,
	security@...nel.org, linux-aio@...ck.org,
	linux-kernel@...r.kernel.org, Mateusz Guzik <mguzik@...hat.com>,
	Petr Matousek <pmatouse@...hat.com>,
	Kent Overstreet <kmo@...erainc.com>,
	Jeff Moyer <jmoyer@...hat.com>, stable@...r.kernel.org
Subject: Re: Revert "aio: fix aio request leak when events are reaped by user
 space"

On Tue, Aug 19, 2014 at 12:54:04PM -0400, Benjamin LaHaise wrote:
> On Tue, Aug 19, 2014 at 07:37:33PM +0300, Dan Aloni wrote:
> > Some testing I've done today indicates that the original commit broke
> > AIO with regard to users that overflow the maximum number of request
> > per IO context (where -EAGAIN is returned).
> > 
> > In fact, it did worse - the attached C program can easily overrun the
> > ring buffer that is responsible for managing the completed requests,
> > and caused notification about their completion never to be returned.
> 
> Argh, that would be a problem.
> 
> ...
> > This reverts commit b34e0e1319b31202eb142dcd9688cf7145a30bf6.
> 
> Reverting isn't okay, as that reintroduces another regression.  We need 
> to come up with a fix for this issue that doesn't reintroduce the other 
> regression for events reaped in user space.  Let me have a look and see 
> what I can come up with...

About the original regression you mention, is there a program you can
indicate that reproduces it? On my setups, the regression testing in 
libaio was not able to detect the current regression too.


-- 
Dan Aloni
--
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/