drm/radeon: take the mode_config mutex when dealing with hpds (v2) crashes

Path	csiph.com!goblin1!goblin2!goblin.stu.neva.ru!gothmog.csi.it!bofh.it!news.nic.it!robomod
From	Joerg Platte <lists@naasa.net>
Newsgroups	linux.kernel
Subject	drm/radeon: take the mode_config mutex when dealing with hpds (v2) crashes
Date	Mon, 24 Aug 2015 05:40:02 +0200
Message-ID	<q0QM2-49d-7@gated-at.bofh.it> (permalink)
X-Original-To	alexander.deucher@amd.com, linux-kernel@vger.kernel.org
X-Greylist	delayed 535 seconds by postgrey-1.27 at vger.kernel.org; Sun, 23 Aug 2015 23:34:40 EDT
User-Agent	Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Icedove/38.0.1
MIME-Version	1.0
Content-Type	text/plain; charset=utf-8; format=flowed
Content-Transfer-Encoding	7bit
Sender	robomod@news.nic.it
List-ID	<linux-kernel.vger.kernel.org>
X-Mailing-List	linux-kernel@vger.kernel.org
Approved	robomod@news.nic.it
Lines	60
Organization	linux.* mail to news gateway
X-Original-Date	Mon, 24 Aug 2015 05:25:43 +0200
X-Original-Message-ID	<55DA8EB7.9000206@naasa.net>
X-Original-Sender	linux-kernel-owner@vger.kernel.org
Xref	csiph.com linux.kernel:1211753

Show key headers only | View raw

Dear Alex,

on my old P4 based non-SMP router your patch (commit 
32d12fc20e3c726ca858d0e5055fb596fce2f8bc in linux stable) crashes on 
Linux 4.1.4 and above. I was only able to take a picture of the whole 
trace https://ferdi.naasa.net/url/jplatte/IMG_3116.JPG

Reverting the patch resolves the issue.

This is my old graphics hardware:
01:00.0 VGA compatible controller: Advanced Micro Devices, Inc. 
[AMD/ATI] RV100 [Radeon 7000 / Radeon VE]

Just for the reference, here is the full patch:
commit 32d12fc20e3c726ca858d0e5055fb596fce2f8bc
Author: Alex Deucher <alexander.deucher@amd.com>
Date:   Fri May 15 11:48:52 2015 -0400

     drm/radeon: take the mode_config mutex when dealing with hpds (v2)

     commit 39fa10f7e21574a70cecf1fed0f9b36535aa68a0 upstream.

     Since we are messing with state in the worker.

     v2: drop the changes in the mst worker

     Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
     Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/gpu/drm/radeon/radeon_irq_kms.c 
b/drivers/gpu/drm/radeon/radeon_irq_kms.c
index 7162c93..f682e53 100644
--- a/drivers/gpu/drm/radeon/radeon_irq_kms.c
+++ b/drivers/gpu/drm/radeon/radeon_irq_kms.c
@@ -79,10 +79,12 @@ static void radeon_hotplug_work_func(struct 
work_struct *work)
         struct drm_mode_config *mode_config = &dev->mode_config;
         struct drm_connector *connector;

+       mutex_lock(&mode_config->mutex);
         if (mode_config->num_connector) {
                 list_for_each_entry(connector, 
&mode_config->connector_list, head)
                         radeon_connector_hotplug(connector);
         }
+       mutex_unlock(&mode_config->mutex);
         /* Just fire off a uevent and let userspace tell us what to do */
         drm_helper_hpd_irq_event(dev);
  }

Is it possible that the mutex is not defined on non-SMP systems? Can you 
help to resolve this regression?

Best regards,
Joerg
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Back to linux.kernel | Previous | Next | Find similar | Unroll thread

Thread

drm/radeon: take the mode_config mutex when dealing with hpds (v2)  crashes Joerg Platte <lists@naasa.net> - 2015-08-24 05:40 +0200

csiph-web