From: Steven Rostedt <rostedt@goodmis.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: mingo@kernel.org, linux-kernel@vger.kernel.org,
torvalds@linux-foundation.org, fweisbec@gmail.com,
oleg@redhat.com, umgwanakikbuti@gmail.com, tglx@linutronix.de
Subject: Re: [PATCH v2 07/12] sched: Robustify preemption leak checks
Date: Wed, 30 Sep 2015 05:35:01 -0400 [thread overview]
Message-ID: <20150930053501.55ebe134@gandalf.local.home> (raw)
In-Reply-To: <20150930072304.285433585@infradead.org>
On Wed, 30 Sep 2015 09:10:42 +0200
Peter Zijlstra <peterz@infradead.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@gmail.com>
> Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Steven Rostedt <rostedt@goodmis.org>
-- Steve
> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
> ---
next prev parent reply other threads:[~2015-09-30 9:35 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-09-30 7:10 [PATCH v2 00/12] sched: Killing PREEMPT_ACTIVE Peter Zijlstra
2015-09-30 7:10 ` [PATCH v2 01/12] sched: Simplify INIT_PREEMPT_COUNT Peter Zijlstra
2015-09-30 9:04 ` Steven Rostedt
2015-09-30 20:39 ` Thomas Gleixner
2015-10-01 13:25 ` Frederic Weisbecker
2015-09-30 7:10 ` [PATCH v2 02/12] sched: Rework TASK_DEAD preemption exception Peter Zijlstra
2015-09-30 7:10 ` [PATCH v2 03/12] sched: Create preempt_count invariant Peter Zijlstra
2015-09-30 9:32 ` Steven Rostedt
2015-09-30 11:13 ` Peter Zijlstra
2015-09-30 13:36 ` Steven Rostedt
2015-09-30 7:10 ` [PATCH v2 04/12] sched: Add preempt argument to __schedule() Peter Zijlstra
2015-09-30 7:10 ` [PATCH v2 05/12] sched: Fix trace_sched_switch() Peter Zijlstra
2015-09-30 7:10 ` [PATCH v2 06/12] sched: Stop setting PREEMPT_ACTIVE Peter Zijlstra
2015-10-01 15:27 ` Frederic Weisbecker
2015-09-30 7:10 ` [PATCH v2 07/12] sched: Robustify preemption leak checks Peter Zijlstra
2015-09-30 9:35 ` Steven Rostedt [this message]
2015-09-30 7:10 ` [PATCH v2 08/12] sched: Simplify preempt_count tests Peter Zijlstra
2015-10-01 15:31 ` Frederic Weisbecker
2015-09-30 7:10 ` [PATCH v2 09/12] sched, x86: Kill saved_preempt_count Peter Zijlstra
2015-10-01 15:40 ` Frederic Weisbecker
2015-09-30 7:10 ` [PATCH v2 10/12] sched: Kill PREEMPT_ACTIVE Peter Zijlstra
2015-10-01 15:41 ` Frederic Weisbecker
2015-09-30 7:10 ` [PATCH v2 11/12] sched: More notrace Peter Zijlstra
2015-09-30 7:10 ` [PATCH v2 12/12] sched: Add preempt_count invariant check Peter Zijlstra
2015-09-30 9:38 ` Steven Rostedt
2015-09-30 11:15 ` Peter Zijlstra
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