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From: Greg KH <greg@kroah.com>
To: Brian King <brking@us.ibm.com>
Cc: Andrew Morton <akpm@osdl.org>,
	linux-kernel@vger.kernel.org,
	linux-hotplug-devel@lists.sourceforge.net
Subject: Re: [PATCH] call_usermodehelper hang
Date: Thu, 08 Apr 2004 22:47:13 +0000	[thread overview]
Message-ID: <20040408224713.GD15125@kroah.com> (raw)
In-Reply-To: <407487A6.8020904@us.ibm.com>

On Wed, Apr 07, 2004 at 05:58:46PM -0500, Brian King wrote:
> The following patch fixes a deadlock experienced when devices are
> being added to a bus both from a user process and eventd process.
> The eventd process was hung waiting on dev->bus->subsys.rwsem which
> was held by another process, which was hung since it was calling 
> call_usermodehelper directly which was hung waiting for work scheduled
> on the eventd workqueue to complete. The patch fixes this by delaying
> the kobject_hotplug work, running it from eventd if possible. 

But why?  Will this not still cause the same deadlock eventually?  The
call_usermodehelper function uses keventd, so what about users who call
that function directly?

Also, you gratitously changed some of the whitespace in the file you
were modifying, which isn't a nice thing to do :)

thanks,

greg k-h


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WARNING: multiple messages have this Message-ID (diff)
From: Greg KH <greg@kroah.com>
To: Brian King <brking@us.ibm.com>
Cc: Andrew Morton <akpm@osdl.org>,
	linux-kernel@vger.kernel.org,
	linux-hotplug-devel@lists.sourceforge.net
Subject: Re: [PATCH] call_usermodehelper hang
Date: Thu, 8 Apr 2004 15:47:13 -0700	[thread overview]
Message-ID: <20040408224713.GD15125@kroah.com> (raw)
In-Reply-To: <407487A6.8020904@us.ibm.com>

On Wed, Apr 07, 2004 at 05:58:46PM -0500, Brian King wrote:
> The following patch fixes a deadlock experienced when devices are
> being added to a bus both from a user process and eventd process.
> The eventd process was hung waiting on dev->bus->subsys.rwsem which
> was held by another process, which was hung since it was calling 
> call_usermodehelper directly which was hung waiting for work scheduled
> on the eventd workqueue to complete. The patch fixes this by delaying
> the kobject_hotplug work, running it from eventd if possible. 

But why?  Will this not still cause the same deadlock eventually?  The
call_usermodehelper function uses keventd, so what about users who call
that function directly?

Also, you gratitously changed some of the whitespace in the file you
were modifying, which isn't a nice thing to do :)

thanks,

greg k-h

  reply	other threads:[~2004-04-08 22:47 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-04-06 18:11 call_usermodehelper hang Brian King
2004-04-07  0:29 ` Andrew Morton
2004-04-07  6:11   ` Greg KH
2004-04-07 14:00     ` Brian King
2004-04-07 22:58     ` [PATCH] " Brian King
2004-04-08 22:47       ` Greg KH [this message]
2004-04-08 22:47         ` Greg KH
2004-04-09 20:42         ` Brian King
2004-04-09 20:42           ` Brian King
2004-04-09 20:53           ` Greg KH
2004-04-09 20:53             ` Greg KH
2004-04-09 21:05             ` Brian King
2004-04-09 21:05               ` Brian King
2004-04-09 21:15             ` Andrew Morton
2004-04-09 21:15               ` Andrew Morton
2004-04-10 16:53               ` Greg KH
2004-04-10 16:53                 ` Greg KH
2004-04-10 20:11                 ` Andrew Morton
2004-04-10 20:11                   ` Andrew Morton
2004-04-12 15:25                   ` Brian King
2004-04-12 15:25                     ` Brian King
2004-04-12 17:46                     ` Andrew Morton
2004-04-12 17:46                       ` Andrew Morton
2004-04-16 17:55                       ` Brian King
2004-04-16 17:55                         ` Brian King
2004-04-12 18:49                   ` Greg KH
2004-04-12 18:49                     ` Greg KH
2004-04-08 23:17       ` Chris Wright
2004-04-07  0:41 ` Chris Wright
2004-04-07  1:46   ` Brian King

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