linux-kernel - Re: [PATCH] sched, cgroup: Use exit hook to avoid use-after-free crash

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: <1293210457.29444.206.camel@laptop>
Date:	Fri, 24 Dec 2010 18:07:37 +0100
From:	Peter Zijlstra <peterz@...radead.org>
To:	Mike Galbraith <efault@....de>
Cc:	Miklos Vajna <vmiklos@...galware.org>,
	shenghui <crosslonelyover@...il.com>,
	kernel-janitors@...r.kernel.org, linux-kernel@...r.kernel.org,
	mingo@...e.hu, Greg KH <greg@...ah.com>,
	Paul Turner <pjt@...gle.com>,
	Yong Zhang <yong.zhang0@...il.com>,
	Li Zefan <lizf@...fujitsu.com>,
	Paul Menage <menage@...gle.com>,
	Balbir Singh <balbir@...ux.vnet.ibm.com>,
	Srivatsa Vaddagiri <vatsa@...ibm.com>
Subject: Re: [PATCH] sched, cgroup: Use exit hook to avoid use-after-free
 crash

On Fri, 2010-12-24 at 17:48 +0100, Mike Galbraith wrote:
> On Fri, 2010-12-24 at 16:59 +0100, Peter Zijlstra wrote:
> 
> > So cgroup moves a task without calling cgroup_subsys::attach() which is
> > odd, but it does have an ::exit method, sadly it calls that _before_
> > re-assigning the task, which means we have to jump through some hoops.
> 
> Could you do the move in cgroup_exit() in the CONFIG_PREEMPT case?

I'm not really comfortable relying on that.. voluntary might just grow a
cond_resched() somewhere in the exit path and lead us down the same
path, also I think that !preempt smp might have the same race.


--
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/