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Message-ID: <20150614123331.GA14645@lerouge>
Date: Sun, 14 Jun 2015 14:33:32 +0200
From: Frederic Weisbecker <fweisbec@...il.com>
To: Fengguang Wu <fengguang.wu@...el.com>
Cc: Ingo Molnar <mingo@...nel.org>,
"Peter Zijlstra (Intel)" <peterz@...radead.org>, LKP <lkp@...org>,
LKML <linux-kernel@...r.kernel.org>
Subject: Re: [sched/preempt] BUG: KASan: out of bounds access in
trace_graph_entry at addr ffff88000d717e48
On Sun, Jun 14, 2015 at 04:55:59PM +0800, Fengguang Wu wrote:
> Hi Frederic,
>
> FYI, there are a number more bug messages showing up after this commit
>
> git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
>
> commit b30f0e3ffedfa52b1d67a302ae5860c49998e5e2
> Author: Frederic Weisbecker <fweisbec@...il.com>
> AuthorDate: Tue May 12 16:41:49 2015 +0200
> Commit: Ingo Molnar <mingo@...nel.org>
> CommitDate: Tue May 19 08:39:12 2015 +0200
>
> sched/preempt: Optimize preemption operations on __schedule() callers
>
> __schedule() disables preemption and some of its callers
> (the preempt_schedule*() family) also set PREEMPT_ACTIVE.
>
> So we have two preempt_count() modifications that could be performed
> at once.
>
> Lets remove the preemption disablement from __schedule() and pull
> this responsibility to its callers in order to optimize preempt_count()
> operations in a single place.
>
> Suggested-by: Linus Torvalds <torvalds@...ux-foundation.org>
> Signed-off-by: Frederic Weisbecker <fweisbec@...il.com>
> Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
> Cc: Peter Zijlstra <peterz@...radead.org>
> Cc: Thomas Gleixner <tglx@...utronix.de>
> Link: http://lkml.kernel.org/r/1431441711-29753-5-git-send-email-fweisbec@gmail.com
> Signed-off-by: Ingo Molnar <mingo@...nel.org>
Do you still see that issue after latest tip:/sched/core. I fixed it a few days ago with:
9a92e3dc6ad02208a014d0d8404ebbd697e3d5ef (preempt: Reorganize the notrace definitions a bit)
4eaca0a887eaee04fc7a3866d0f5b51b34030dfa (preempt: Use preempt_schedule_context() as the official tracing preemption point)
be690035df893385ceaac2323b29be1fb7f2a67f (sched: Make preempt_schedule_context() function-tracing safe)
But maybe there are other issues remaining.
Thanks.
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