[PATCH] drm/i915: Fix possible null pointer dereference after drm_dbg_printer conversion

[Tvrtko Ursulin]

On 19/02/2024 20:02, Rodrigo Vivi wrote:
> On Mon, Feb 19, 2024 at 01:14:23PM +0000, Tvrtko Ursulin wrote:
>> From: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
>>
>> Request can be NULL if no guilty request was identified so simply use
>> engine->i915 instead.
>>
>> Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
>> Fixes: d50892a9554c ("drm/i915: switch from drm_debug_printer() to device specific drm_dbg_printer()")
>> Reported-by: Dan Carpenter <dan.carpenter at linaro.org>
>> Cc: Jani Nikula <jani.nikula at intel.com>
>> Cc: Luca Coelho <luciano.coelho at intel.com>
>> Cc: Maxime Ripard <mripard at kernel.org>
>> Cc: Jani Nikula <jani.nikula at linux.intel.com>
> 
> Reviewed-by: Rodrigo Vivi <rodrigo.vivi at intel.com>

Thanks Rodrigo!

Given how d50892a9554c landed via drm-misc-next, Maxime or Thomas - 
could you take this via drm-misc-next-fixes or if there will be another 
drm-misc-next pull request?

Regards,

Tvrtko

> 
>> ---
>>   drivers/gpu/drm/i915/gt/intel_engine_heartbeat.c | 4 ++--
>>   1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/i915/gt/intel_engine_heartbeat.c b/drivers/gpu/drm/i915/gt/intel_engine_heartbeat.c
>> index 5f8d86e25993..8d4bb95f8424 100644
>> --- a/drivers/gpu/drm/i915/gt/intel_engine_heartbeat.c
>> +++ b/drivers/gpu/drm/i915/gt/intel_engine_heartbeat.c
>> @@ -96,8 +96,8 @@ static void heartbeat_commit(struct i915_request *rq,
>>   static void show_heartbeat(const struct i915_request *rq,
>>   			   struct intel_engine_cs *engine)
>>   {
>> -	struct drm_printer p = drm_dbg_printer(&rq->i915->drm, DRM_UT_DRIVER,
>> -					       "heartbeat");
>> +	struct drm_printer p =
>> +		drm_dbg_printer(&engine->i915->drm, DRM_UT_DRIVER, "heartbeat");
>>   
>>   	if (!rq) {
>>   		intel_engine_dump(engine, &p,
>> -- 
>> 2.40.1
>>