linux-kernel - Re: [PATCH v2 07/12] sched: Robustify preemption leak checks

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]

Date:	Wed, 30 Sep 2015 05:35:01 -0400
From:	Steven Rostedt <rostedt@...dmis.org>
To:	Peter Zijlstra <peterz@...radead.org>
Cc:	mingo@...nel.org, linux-kernel@...r.kernel.org,
	torvalds@...ux-foundation.org, fweisbec@...il.com, oleg@...hat.com,
	umgwanakikbuti@...il.com, tglx@...utronix.de
Subject: Re: [PATCH v2 07/12] sched: Robustify preemption leak checks

On Wed, 30 Sep 2015 09:10:42 +0200
Peter Zijlstra <peterz@...radead.org> wrote:

> When we warn about a preempt_count leak; reset the preempt_count to
> the known good value such that the problem does not ripple forward.
> 
> This is most important on x86 which has a per cpu preempt_count that is
> not saved/restored (after this series). So if you schedule with an
> invalid (!2*PREEMPT_DISABLE_OFFSET) preempt_count the next task is
> messed up too.
> 
> Enforcing this invariant limits the borkage to just the one task.
> 
> Reviewed-by: Frederic Weisbecker <fweisbec@...il.com>
> Reviewed-by: Thomas Gleixner <tglx@...utronix.de>

Reviewed-by: Steven Rostedt <rostedt@...dmis.org>

-- Steve

> Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
> ---

--
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/