linux-kernel - Re: [PATCH] avoid race condition in pick_next_task_fair in kernel/sched

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]

Date:	Tue, 29 Jun 2010 13:35:16 +0200
From:	Peter Zijlstra <peterz@...radead.org>
To:	shenghui <crosslonelyover@...il.com>
Cc:	kernel-janitors@...r.kernel.org, linux-kernel@...r.kernel.org,
	mingo@...e.hu, Greg KH <greg@...ah.com>
Subject: Re: [PATCH] avoid race condition in pick_next_task_fair in 
 kernel/sched_fair.c

On Tue, 2010-06-29 at 19:24 +0800, shenghui wrote:

> I wonder is there any chance set_next_entity() can get NULL for
> parameter se if so?

Well, if your machine crashes that way, maybe, but I haven't seen that
happen in a long while.

> And will you please give me some instructions on where rq->lock
> is required?

Pretty much everywhere, if you look at sched.c the only sched_class
method not called with rq->lock held is ::task_fork().

The interesting bits are that schedule()->pre_schedule()/idle_balance()
can drop rq->lock as well as ->select_task_rq().



--
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/