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From: Alessandro Zummo <a.zummo@towertech.it>
To: Tejun Heo <tj@kernel.org>
Cc: Sasha Levin <sasha.levin@oracle.com>, Greg KH <greg@kroah.com>,
	rtc-linux@googlegroups.com, LKML <linux-kernel@vger.kernel.org>
Subject: Re: kernfs/rtc: circular dependency between kernfs and ops_lock
Date: Mon, 24 Feb 2014 12:04:27 +0100	[thread overview]
Message-ID: <20140224120427.6394d5dd@linux.lan.towertech.it> (raw)
In-Reply-To: <20140222205217.GC16272@mtj.dyndns.org>

On Sat, 22 Feb 2014 15:52:17 -0500
Tejun Heo <tj@kernel.org> wrote:

> The problem is rtc_device_unregister().  It grabs rtc->ops_lock and
> then tries to remove the sysfs files.  Some of those sysfs file
> implementations acquire rtc->ops_lock, so it of course can lead to
> deadlocks.  One can't try to delete a sysfs file which acquires a lock
> while holding the same lock.

 Pretty interesting indeed. One option would be to remove
 the sys files before acquiring the lock. But I wonder
 if this could lead to other issues.

-- 

 Best regards,

 Alessandro Zummo,
  Tower Technologies - Torino, Italy

  http://www.towertech.it


  reply	other threads:[~2014-02-24 11:10 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-02-22 17:51 kernfs/rtc: circular dependency between kernfs and ops_lock Sasha Levin
2014-02-22 20:52 ` Tejun Heo
2014-02-24 11:04   ` Alessandro Zummo [this message]
2014-03-25 21:52     ` Sasha Levin
2014-03-25 22:39       ` Alessandro Zummo
2014-03-26  0:19         ` Sasha Levin
2014-03-30  0:28           ` Sasha Levin
2014-03-30 16:04             ` Sasha Levin
2014-03-31  9:46               ` Alessandro Zummo
2014-03-31  9:52                 ` Lars-Peter Clausen
2014-03-31 10:43                   ` Alessandro Zummo
2014-03-31 11:07                     ` Lars-Peter Clausen
2014-03-31 12:03                       ` Alessandro Zummo
2014-03-31 12:19                         ` Lars-Peter Clausen
2014-04-02 22:51                           ` Sasha Levin

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