Message-ID: <4AF9923E.9020603@lwfinger.net>
Date: Tue, 10 Nov 2009 10:18:06 -0600
From: Larry Finger <Larry.Finger@lwfinger.net>
MIME-Version: 1.0
To: "John W. Linville" <linville@tuxdriver.com>
CC: Luca Niccoli <lultimouomo@gmail.com>,
	linux-wireless@vger.kernel.org, stable@kernel.org
Subject: Re: Please backport [PATCH] rtl8187: Fix kernel oops when device
 is removed when LEDS enabled (Bugzilla #14539)
References: <4e9568870911100747o6088ca86lf168849e6a42b91d@mail.gmail.com> <20091110155511.GE12682@tuxdriver.com>
In-Reply-To: <20091110155511.GE12682@tuxdriver.com>
Content-Type: text/plain; charset=ISO-8859-1
Sender: linux-wireless-owner@vger.kernel.org

On 11/10/2009 09:55 AM, John W. Linville wrote:
> On Tue, Nov 10, 2009 at 04:47:50PM +0100, Luca Niccoli wrote:
>> I'm running 2.6.31 (from debian source) and I experienced hard freezes
>> on removing the module or disconnecting the USB card.
>> The patch at [1] seems to have fixed the problem, so it would be nice
>> if it could be included in the 2.6.31 branch.
>> Note that I was not experiencing the freezes with the distribution
>> kernel, just with a self compiled one (without source modifications
>> though, only config).
>> Cheers,
>>
>> Luca
>>
>> (For further info please Cc: me)
>>
>> [1]
>> http://marc.info/?l=linux-wireless&m=125731443329754&w=2
> 
> This has already been sent with the proper tagging to make the stable
> crew aware of it...
> 
> Thanks,
> 
> John
> 
> commit 37b12dd2b07b4d7dc222a5f7f88b25cec532b2aa
> Author: Larry Finger <Larry.Finger@lwfinger.net>
> Date:   Wed Nov 4 00:00:25 2009 -0600
> 
>     rtl8187: Fix kernel oops when device is removed when LEDS enabled
>     
>     As reported by Rick Farina (sidhayn@gmail.com), removing the RTL8187
>     USB stick, or unloading the driver rtl8187 using rmmod will cause a
>     kernel oops.  There are at least two forms of the failure, (1) BUG:
>     Scheduling while atomic, and (2) a fatal kernel page fault. This
>     problem is reported in Bugzilla #14539.
>     
>     This problem does not occur for kernel 2.6.31, but does for 2.6.32-rc2,
>     thus it is technically a regression; however, bisection did not locate
>     any faulty patch. The fix was found by comparing the faulty code in
>     rtl8187 with p54usb.  My interpretation is that the handling of work
>     queues in mac80211 changed enough to the LEDs to be unregistered
>     before tasks on the work queues are cancelled. Previously, these
>     actions could be done in either order.
>     
>     (Herton Ronaldo Krzesinski <herton@mandriva.com.br> reports that the
>     code is the same in 2.6.31, so this may be a candidate for 2.6.31.x.
>     -- JWL)
>     
>     Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
>     Reported-by: Rick Farina <sidhayn@gmail.com>
>     Tested-by: Rick Farina <sidhayn@gmail.com>
>     Cc: stable@kernel.org
>     Signed-off-by: John W. Linville <linville@tuxdriver.com>

Additionally, that patch has just made it to mainline. It was not there until I
did a git pull this morning.

Larry