linux-kernel - Re: [lm-sensors] [PATCH] x86/hwmon: avoid deadlock on CPU removal in pkgtemp

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: <20100915015936.GE8081@ericsson.com>
Date:	Tue, 14 Sep 2010 18:59:36 -0700
From:	Guenter Roeck <guenter.roeck@...csson.com>
To:	Fenghua Yu <fenghua.yu@...el.com>
CC:	Jan Beulich <JBeulich@...ell.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"lm-sensors@...sensors.org" <lm-sensors@...sensors.org>
Subject: Re: [lm-sensors] [PATCH] x86/hwmon: avoid deadlock on CPU removal
 in pkgtemp

On Tue, Sep 14, 2010 at 08:13:00PM -0400, Fenghua Yu wrote:
> On Mon, Sep 13, 2010 at 03:11:05AM -0700, Jan Beulich wrote:
> > pkgtemp_device_remove(), holding the list protecting mutex, calls
> > pkgtemp_device_add(), which itself wants to acquire the same mutex.
> > Holding the mutex over the entire loop body in pkgtemp_device_remove()
> > isn't really necessary, as long as the loop gets exited after
> > processing the matched CPU.
> > 
> > Once exiting the loop after removing an eventual match, there's no
> > need for using the "safe" list iterator anymore.
> > 
> > Signed-off-by: Jan Beulich <jbeulich@...ell.com>
> > Cc: Fenghua Yu <fenghua.yu@...el.com>
> > 
> > ---
> >  drivers/hwmon/pkgtemp.c |    7 ++++---
> >  1 file changed, 4 insertions(+), 3 deletions(-)
> > 
> > --- linux-2.6.36-rc4/drivers/hwmon/pkgtemp.c	2010-09-13 08:45:03.000000000 +0200
> > +++ 2.6.36-rc4-x86-pkgtemp-remove-deadlock/drivers/hwmon/pkgtemp.c	2010-09-03 17:54:30.000000000 +0200
> > @@ -339,17 +339,18 @@ exit:
> >  #ifdef CONFIG_HOTPLUG_CPU
> >  static void pkgtemp_device_remove(unsigned int cpu)
> 
> I already sent a  fix patch before. I'll push it to Linus.
> 
Guess it got lost. Re-sending it might have helped, or adding an Acked-by to this patch.

Guenter
--
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/