* [bug report] drm/i915: Small compaction of the engine init code
@ 2016-12-15 20:44 Dan Carpenter
2016-12-15 20:54 ` Chris Wilson
0 siblings, 1 reply; 4+ messages in thread
From: Dan Carpenter @ 2016-12-15 20:44 UTC (permalink / raw)
To: Tvrtko Ursulin; +Cc: intel-gfx, dri-devel
Hello Tvrtko Ursulin,
The patch a19d6ff29a82: "drm/i915: Small compaction of the engine
init code" from Jun 23, 2016, leads to the following static checker
warning:
drivers/gpu/drm/i915/intel_lrc.c:1973 logical_render_ring_init()
warn: passing freed memory 'engine'
drivers/gpu/drm/i915/intel_lrc.c
1970
1971 ret = logical_ring_init(engine);
1972 if (ret) {
1973 lrc_destroy_wa_ctx_obj(engine);
The problem is that logical_ring_init() frees "engine" on the error
path so this is a use after free.
1974 }
1975
1976 return ret;
1977 }
regards,
dan carpenter
_______________________________________________
Intel-gfx mailing list
Intel-gfx@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/intel-gfx
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [bug report] drm/i915: Small compaction of the engine init code
2016-12-15 20:44 [bug report] drm/i915: Small compaction of the engine init code Dan Carpenter
@ 2016-12-15 20:54 ` Chris Wilson
2016-12-16 8:02 ` [Intel-gfx] " Tvrtko Ursulin
0 siblings, 1 reply; 4+ messages in thread
From: Chris Wilson @ 2016-12-15 20:54 UTC (permalink / raw)
To: Dan Carpenter; +Cc: intel-gfx, dri-devel
On Thu, Dec 15, 2016 at 11:44:13PM +0300, Dan Carpenter wrote:
> Hello Tvrtko Ursulin,
>
> The patch a19d6ff29a82: "drm/i915: Small compaction of the engine
> init code" from Jun 23, 2016, leads to the following static checker
> warning:
>
> drivers/gpu/drm/i915/intel_lrc.c:1973 logical_render_ring_init()
> warn: passing freed memory 'engine'
>
> drivers/gpu/drm/i915/intel_lrc.c
> 1970
> 1971 ret = logical_ring_init(engine);
> 1972 if (ret) {
> 1973 lrc_destroy_wa_ctx_obj(engine);
>
> The problem is that logical_ring_init() frees "engine" on the error
> path so this is a use after free.
And calls lrc_destroy_wa_ctx_obj() in the process. So we can
diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
index 067394b0a769..1c1bad8ae7b0 100644
--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -1940,12 +1940,7 @@ int logical_render_ring_init(struct intel_engine_cs *engine)
ret);
}
- ret = logical_ring_init(engine);
- if (ret) {
- lrc_destroy_wa_ctx_obj(engine);
- }
-
- return ret;
+ return logical_ring_init(engine);
}
int logical_xcs_ring_init(struct intel_engine_cs *engine)
--
Chris Wilson, Intel Open Source Technology Centre
_______________________________________________
Intel-gfx mailing list
Intel-gfx@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/intel-gfx
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [Intel-gfx] [bug report] drm/i915: Small compaction of the engine init code
2016-12-15 20:54 ` Chris Wilson
@ 2016-12-16 8:02 ` Tvrtko Ursulin
2016-12-16 8:38 ` Tvrtko Ursulin
0 siblings, 1 reply; 4+ messages in thread
From: Tvrtko Ursulin @ 2016-12-16 8:02 UTC (permalink / raw)
To: Chris Wilson, Dan Carpenter, Tvrtko Ursulin, intel-gfx, dri-devel
On 15/12/2016 20:54, Chris Wilson wrote:
> On Thu, Dec 15, 2016 at 11:44:13PM +0300, Dan Carpenter wrote:
>> Hello Tvrtko Ursulin,
>>
>> The patch a19d6ff29a82: "drm/i915: Small compaction of the engine
>> init code" from Jun 23, 2016, leads to the following static checker
>> warning:
>>
>> drivers/gpu/drm/i915/intel_lrc.c:1973 logical_render_ring_init()
>> warn: passing freed memory 'engine'
>>
>> drivers/gpu/drm/i915/intel_lrc.c
>> 1970
>> 1971 ret = logical_ring_init(engine);
>> 1972 if (ret) {
>> 1973 lrc_destroy_wa_ctx_obj(engine);
>>
>> The problem is that logical_ring_init() frees "engine" on the error
>> path so this is a use after free.
>
> And calls lrc_destroy_wa_ctx_obj() in the process. So we can
>
> diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
> index 067394b0a769..1c1bad8ae7b0 100644
> --- a/drivers/gpu/drm/i915/intel_lrc.c
> +++ b/drivers/gpu/drm/i915/intel_lrc.c
> @@ -1940,12 +1940,7 @@ int logical_render_ring_init(struct intel_engine_cs *engine)
> ret);
> }
>
> - ret = logical_ring_init(engine);
> - if (ret) {
> - lrc_destroy_wa_ctx_obj(engine);
> - }
> -
> - return ret;
> + return logical_ring_init(engine);
> }
>
> int logical_xcs_ring_init(struct intel_engine_cs *engine)
>
I've marked this as TODO for later.
Interesting that it was detected only now. Even more so, the referenced
commit just moved the code around.
I think that the real issue was introduced around "drm/i915/gen8:
Re-order init pipe_control in lrc mode".
Regards,
Tvrtko
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [Intel-gfx] [bug report] drm/i915: Small compaction of the engine init code
2016-12-16 8:02 ` [Intel-gfx] " Tvrtko Ursulin
@ 2016-12-16 8:38 ` Tvrtko Ursulin
0 siblings, 0 replies; 4+ messages in thread
From: Tvrtko Ursulin @ 2016-12-16 8:38 UTC (permalink / raw)
To: Chris Wilson, Dan Carpenter, Tvrtko Ursulin, intel-gfx, dri-devel
On 16/12/2016 08:02, Tvrtko Ursulin wrote:
>
> On 15/12/2016 20:54, Chris Wilson wrote:
>> On Thu, Dec 15, 2016 at 11:44:13PM +0300, Dan Carpenter wrote:
>>> Hello Tvrtko Ursulin,
>>>
>>> The patch a19d6ff29a82: "drm/i915: Small compaction of the engine
>>> init code" from Jun 23, 2016, leads to the following static checker
>>> warning:
>>>
>>> drivers/gpu/drm/i915/intel_lrc.c:1973 logical_render_ring_init()
>>> warn: passing freed memory 'engine'
>>>
>>> drivers/gpu/drm/i915/intel_lrc.c
>>> 1970
>>> 1971 ret = logical_ring_init(engine);
>>> 1972 if (ret) {
>>> 1973 lrc_destroy_wa_ctx_obj(engine);
>>>
>>> The problem is that logical_ring_init() frees "engine" on the error
>>> path so this is a use after free.
>>
>> And calls lrc_destroy_wa_ctx_obj() in the process. So we can
>>
>> diff --git a/drivers/gpu/drm/i915/intel_lrc.c
>> b/drivers/gpu/drm/i915/intel_lrc.c
>> index 067394b0a769..1c1bad8ae7b0 100644
>> --- a/drivers/gpu/drm/i915/intel_lrc.c
>> +++ b/drivers/gpu/drm/i915/intel_lrc.c
>> @@ -1940,12 +1940,7 @@ int logical_render_ring_init(struct
>> intel_engine_cs *engine)
>> ret);
>> }
>>
>> - ret = logical_ring_init(engine);
>> - if (ret) {
>> - lrc_destroy_wa_ctx_obj(engine);
>> - }
>> -
>> - return ret;
>> + return logical_ring_init(engine);
>> }
>>
>> int logical_xcs_ring_init(struct intel_engine_cs *engine)
>>
>
> I've marked this as TODO for later.
>
> Interesting that it was detected only now. Even more so, the referenced
> commit just moved the code around.
>
> I think that the real issue was introduced around "drm/i915/gen8:
> Re-order init pipe_control in lrc mode".
Actually it was probably the dynamic engine allocation patch.
Regards,
Tvrtko
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2016-12-16 8:38 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2016-12-15 20:44 [bug report] drm/i915: Small compaction of the engine init code Dan Carpenter
2016-12-15 20:54 ` Chris Wilson
2016-12-16 8:02 ` [Intel-gfx] " Tvrtko Ursulin
2016-12-16 8:38 ` Tvrtko Ursulin
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox