linux-kernel - Re: [PATCH RT 2/4] Revert "timers: do not raise softirq unconditionally"

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: <1427250833.3459.4.camel@gmail.com>
Date:	Wed, 25 Mar 2015 03:33:53 +0100
From:	Mike Galbraith <umgwanakikbuti@...il.com>
To:	Sebastian Andrzej Siewior <bigeasy@...utronix.de>
Cc:	Steven Rostedt <rostedt@...dmis.org>, linux-kernel@...r.kernel.org,
	linux-rt-users <linux-rt-users@...r.kernel.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	Carsten Emde <C.Emde@...dl.org>,
	John Kacur <jkacur@...hat.com>,
	Paul Gortmaker <paul.gortmaker@...driver.com>
Subject: Re: [PATCH RT 2/4] Revert "timers: do not raise softirq
 unconditionally"

On Tue, 2015-03-24 at 19:10 +0100, Sebastian Andrzej Siewior wrote:
> * Steven Rostedt | 2015-03-19 12:26:11 [-0400]:
> 
> >On Thu, 19 Mar 2015 09:17:09 +0100
> >Mike Galbraith <umgwanakikbuti@...il.com> wrote:
> >
> >
> >> (aw crap, let's go shopping)... so why is the one in timer.c ok?
> >
> >It's not. Sebastian, you said there were no other cases of rt_mutexes
> >being taken in hard irq context. Looks like timer.c has one.
> 
> If you refer to switch_timer_base() then this one is not taken in
> hard-irq context. The callchain is:
> 
> lock_timer_base() (with spin_lock_irqsave(&base->lock, *flags) which
>                    makes it a sleeping lock or lockdep would scream)
>   -> switch_timer_base()
>      -> spin_trylock() (not in hardirq conteyt)

Nah, I was referring to get_next_timer_interrupt() because I saw that
rt_spin_unlock_after_trylock_in_irq(&base->lock) sitting there.

	-Mike

--
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/