From: Gabriel Krisman Bertazi <krisman@collabora.co.uk>
To: Fengguang Wu <fengguang.wu@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>,
        #etnaviv@wfg-t540p.sh.intel.com, #vmwgfx@wfg-t540p.sh.intel.com,
        Daniel Vetter <daniel.vetter@ffwll.ch>,
        Joonas Lahtinen <joonas.lahtinen@linux.intel.com>,
        linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org,
        Alex Deucher <alexander.deucher@amd.com>, LKP <lkp@01.org>
Subject: Re: [drm] 4e64e5539d [ 1138.272031] NMI watchdog: BUG: soft lockup - CPU#0 stuck for 23s! [swapper:1]
Organization: Collabora
References: <20170329042937.ihpexoorzrnd3zqn@wfg-t540p.sh.intel.com>
Date: Wed, 29 Mar 2017 22:37:09 -0300
In-Reply-To: <20170329042937.ihpexoorzrnd3zqn@wfg-t540p.sh.intel.com>
        (Fengguang Wu's message of "Wed, 29 Mar 2017 12:29:37 +0800")
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Fengguang Wu <fengguang.wu@intel.com> writes:

> Hi Chris,
>
>>+------------------------------------------+------------+------------+-----------+---------------+
>>|                                          | 17aad8a340 | 4e64e5539d | v4.11-rc3 | next-20170320 |
>>+------------------------------------------+------------+------------+-----------+---------------+
>>| boot_successes                           | 0          | 0          | 0         | 0             |
>>| boot_failures                            | 1220       | 312        | 324       | 63            |
>>| BUG:unable_to_handle_kernel              | 1220       | 312        | 324       | 63            |
>>| Oops:#[##]                               | 1220       | 312        | 324       | 63            |
>>| Kernel_panic-not_syncing:Fatal_exception | 1220       | 312        | 324       | 63            |
>>+------------------------------------------+------------+------------+-----------+---------------+
>>
>>[  195.344608] [TTM] Zone  kernel: Available graphics memory: 200980 kiB
>>[  195.345639] [TTM] Initializing pool allocator
>>[  195.346363] [TTM] Initializing DMA pool allocator
>>[  195.347754] [drm] Initialized bochs-drm 1.0.0 20130925 for 0000:00:02.0 on minor 0
>>[  195.349292] irq event stamp: 5513
>>[  195.349293] BUG: unable to handle kernel NULL pointer dereference at 0000000000000620
>>[  195.349309] IP: __lock_acquire+0xc8/0xfe6
>
>
> Sorry that looks like an old bug. While the below soft lockup
> call trace looks more related to the code change.
>

Hi,

For the record, I suspect the Null pointer dereference is already fixed in the tip
of drm-misc-next.  See 4fa13dbe8c86 ("drm: bochs: Don't remove uninitialized fbdev framebuffer").

-- 
Gabriel Krisman Bertazi