linux-kernel - Re: [RFC][PATCH 05/11] sched: Add preempt argument to _

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: <20150929113026.6b77b5c4@gandalf.local.home>
Date:	Tue, 29 Sep 2015 11:30:26 -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: [RFC][PATCH 05/11] sched: Add preempt argument to __schedule()

On Tue, 29 Sep 2015 11:28:39 -0400
Steven Rostedt <rostedt@...dmis.org> wrote:

> On Tue, 29 Sep 2015 11:28:30 +0200
> Peter Zijlstra <peterz@...radead.org> wrote:
> 
> > There is only a single PREEMPT_ACTIVE use in the regular __schedule()
> > path and that is to circumvent the task->state check. Since the code
> > setting PREEMPT_ACTIVE is the immediate caller of __schedule() we can
> > replace this with a function argument.
> > 
> > Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
> > ---
> 
> Reviewed-by: Steven Rostedt <rostedt@...dmis.org>

I just want to note that this scared me at first, because __schedule()
can be traced by the function tracer that can also do a
preempt_enable() which would schedule if preemption was enabled. But it
looks as __schedule() is always called with preemption disabled, thus,
no worries.

-- Steve

--
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/