[PATCH] drm/i915: Return NULL on error in active_instance

[PATCH] drm/i915: Return NULL on error in active_instance

[Joonas Lahtinen]

Avoid returning &node->base when node is NULL due to OOM
during GFP_ATOMIC allocation.

Discovered using AI-assisted static analysis confirmed by
Intel Product Security.

Reported-by: Martin Hodo <martin.hodo@intel.com>
Fixes: bfaae47db3c0 ("drm/i915: make lockdep slightly happier about execbuf.")
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Simona Vetter <simona.vetter@ffwll.ch>
Cc: <stable@vger.kernel.org> # v5.13+
Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
---
 drivers/gpu/drm/i915/i915_active.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/i915_active.c b/drivers/gpu/drm/i915/i915_active.c
index 5cb7a72774a0..aa77def0bc0d 100644
--- a/drivers/gpu/drm/i915/i915_active.c
+++ b/drivers/gpu/drm/i915/i915_active.c
@@ -318,7 +318,7 @@ active_instance(struct i915_active *ref, u64 idx)
 	 */
 	node = kmem_cache_alloc(slab_cache, GFP_ATOMIC);
 	if (!node)
-		goto out;
+		goto err;
 
 	__i915_active_fence_init(&node->base, NULL, node_retire);
 	node->ref = ref;
@@ -332,6 +332,11 @@ active_instance(struct i915_active *ref, u64 idx)
 	spin_unlock_irq(&ref->tree_lock);
 
 	return &node->base;
+
+err:
+	spin_unlock_irq(&ref->tree_lock);
+
+	return NULL;
 }
 
 void __i915_active_init(struct i915_active *ref,
-- 
2.54.0

Re: [PATCH] drm/i915: Return NULL on error in active_instance

[Sebastian Brzezinka]

Hi Joonas,

On Wed Jun 24, 2026 at 11:09 AM CEST, Joonas Lahtinen wrote:
> Avoid returning &node->base when node is NULL due to OOM
> during GFP_ATOMIC allocation.
>
> Discovered using AI-assisted static analysis confirmed by
> Intel Product Security.
>
> Reported-by: Martin Hodo <martin.hodo@intel.com>
> Fixes: bfaae47db3c0 ("drm/i915: make lockdep slightly happier about execbuf.")
> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
> Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
> Cc: Simona Vetter <simona.vetter@ffwll.ch>
> Cc: <stable@vger.kernel.org> # v5.13+
> Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
> ---
Looks good.
Reviewed-by: Sebastian Brzezinka <sebastian.brzezinka@intel.com>

-- 
Best regards,
Sebastian

Re: [PATCH] drm/i915: Return NULL on error in active_instance

[Sebastian Brzezinka]

Hi,
On Wed Jun 24, 2026 at 11:09 AM CEST, Joonas Lahtinen wrote:
> Avoid returning &node->base when node is NULL due to OOM
> during GFP_ATOMIC allocation.
>
> Discovered using AI-assisted static analysis confirmed by
> Intel Product Security.
>
> Reported-by: Martin Hodo <martin.hodo@intel.com>
> Fixes: bfaae47db3c0 ("drm/i915: make lockdep slightly happier about execbuf.")
> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
> Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
> Cc: Simona Vetter <simona.vetter@ffwll.ch>
> Cc: <stable@vger.kernel.org> # v5.13+
> Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
> ---
>  drivers/gpu/drm/i915/i915_active.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_active.c b/drivers/gpu/drm/i915/i915_active.c
> index 5cb7a72774a0..aa77def0bc0d 100644
> --- a/drivers/gpu/drm/i915/i915_active.c
> +++ b/drivers/gpu/drm/i915/i915_active.c
> @@ -318,7 +318,7 @@ active_instance(struct i915_active *ref, u64 idx)
>  	 */
>  	node = kmem_cache_alloc(slab_cache, GFP_ATOMIC);
>  	if (!node)
> -		goto out;
> +		goto err;
just a nit: this jump is not neccesery, you could return early.

-- 
Best regards,
Sebastian

Re: [PATCH] drm/i915: Return NULL on error in active_instance

[Joonas Lahtinen]

Quoting Sebastian Brzezinka (2026-06-24 12:27:07)
> Hi,
> On Wed Jun 24, 2026 at 11:09 AM CEST, Joonas Lahtinen wrote:
> > Avoid returning &node->base when node is NULL due to OOM
> > during GFP_ATOMIC allocation.
> >
> > Discovered using AI-assisted static analysis confirmed by
> > Intel Product Security.

<SNIP>

> > +++ b/drivers/gpu/drm/i915/i915_active.c
> > @@ -318,7 +318,7 @@ active_instance(struct i915_active *ref, u64 idx)
> >        */
> >       node = kmem_cache_alloc(slab_cache, GFP_ATOMIC);
> >       if (!node)
> > -             goto out;
> > +             goto err;
> just a nit: this jump is not neccesery, you could return early.

We specifically want to embrace the onion error handling idiom with goto
rather than doing the spinlock release inline here.

Preferred error handling should look more like:

	if (!try_lock(lock))
		goto err;

	mem = alloc();
	if (!mem)
		goto err_lock;

	if (!bla_bla(mem, bar))
		goto err_mem;

	...

err_mem:
	free(mem);
err_lock:
	unlock(lock);
err:
	return ret;

Rather than:

	if (!try_lock(lock))
		return ret;

	mem = alloc();
	if (!mem)
	{
		unlock(lock);
		return ret;
	}

	if (!bla_bla(mem, bar))
	{
		free(mem);
		unlock(lock);
		return ret;
	}

	...

Regards, Joonas

Re: [PATCH] drm/i915: Return NULL on error in active_instance

[Sebastian Brzezinka]

On Wed Jun 24, 2026 at 12:24 PM CEST, Joonas Lahtinen wrote:
> Quoting Sebastian Brzezinka (2026-06-24 12:27:07)
>> Hi,
>> On Wed Jun 24, 2026 at 11:09 AM CEST, Joonas Lahtinen wrote:
>> > Avoid returning &node->base when node is NULL due to OOM
>> > during GFP_ATOMIC allocation.
>> >
>> > Discovered using AI-assisted static analysis confirmed by
>> > Intel Product Security.
>
> <SNIP>
>
>> > +++ b/drivers/gpu/drm/i915/i915_active.c
>> > @@ -318,7 +318,7 @@ active_instance(struct i915_active *ref, u64 idx)
>> >        */
>> >       node = kmem_cache_alloc(slab_cache, GFP_ATOMIC);
>> >       if (!node)
>> > -             goto out;
>> > +             goto err;
>> just a nit: this jump is not neccesery, you could return early.
>
> We specifically want to embrace the onion error handling idiom with goto
> rather than doing the spinlock release inline here.
>
> Preferred error handling should look more like:
>
> 	if (!try_lock(lock))
> 		goto err;
>
> 	mem = alloc();
> 	if (!mem)
> 		goto err_lock;
>
> 	if (!bla_bla(mem, bar))
> 		goto err_mem;
>
> 	...
>
> err_mem:
> 	free(mem);
> err_lock:
> 	unlock(lock);
> err:
> 	return ret;
>
> Rather than:
>
> 	if (!try_lock(lock))
> 		return ret;
>
> 	mem = alloc();
> 	if (!mem)
> 	{
> 		unlock(lock);
> 		return ret;
> 	}
>
> 	if (!bla_bla(mem, bar))
> 	{
> 		free(mem);
> 		unlock(lock);
> 		return ret;
> 	}
>
> 	...
>
> Regards, Joonas
Good to know, thanks for the explanation.

-- 
Best regards,
Sebastian

Re: [PATCH] drm/i915: Return NULL on error in active_instance

[Maarten Lankhorst]

Hi,

On 6/24/26 11:09, Joonas Lahtinen wrote:
> Avoid returning &node->base when node is NULL due to OOM
> during GFP_ATOMIC allocation.
> 
> Discovered using AI-assisted static analysis confirmed by
> Intel Product Security.
> 
> Reported-by: Martin Hodo <martin.hodo@intel.com>
> Fixes: bfaae47db3c0 ("drm/i915: make lockdep slightly happier about execbuf.")
> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
> Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
> Cc: Simona Vetter <simona.vetter@ffwll.ch>
> Cc: <stable@vger.kernel.org> # v5.13+
> Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
> ---
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>

>  drivers/gpu/drm/i915/i915_active.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_active.c b/drivers/gpu/drm/i915/i915_active.c
> index 5cb7a72774a0..aa77def0bc0d 100644
> --- a/drivers/gpu/drm/i915/i915_active.c
> +++ b/drivers/gpu/drm/i915/i915_active.c
> @@ -318,7 +318,7 @@ active_instance(struct i915_active *ref, u64 idx)
>  	 */
>  	node = kmem_cache_alloc(slab_cache, GFP_ATOMIC);
>  	if (!node)
> -		goto out;
> +		goto err;
>  
>  	__i915_active_fence_init(&node->base, NULL, node_retire);
>  	node->ref = ref;
> @@ -332,6 +332,11 @@ active_instance(struct i915_active *ref, u64 idx)
>  	spin_unlock_irq(&ref->tree_lock);
>  
>  	return &node->base;
> +
> +err:
> +	spin_unlock_irq(&ref->tree_lock);
> +
> +	return NULL;
>  }
>  
>  void __i915_active_init(struct i915_active *ref,

✗ i915.CI.BAT: failure for drm/i915: Return NULL on error in active_instance

[Patchwork]

[-- Attachment #1: Type: text/plain, Size: 2500 bytes --]

== Series Details ==

Series: drm/i915: Return NULL on error in active_instance
URL   : https://patchwork.freedesktop.org/series/169089/
State : failure

== Summary ==

CI Bug Log - changes from CI_DRM_18714 -> Patchwork_169089v1
====================================================

Summary
-------

  **FAILURE**

  Serious unknown changes coming with Patchwork_169089v1 absolutely need to be
  verified manually.
  
  If you think the reported changes have nothing to do with the changes
  introduced in Patchwork_169089v1, please notify your bug team (I915-ci-infra@lists.freedesktop.org) to allow them
  to document this new failure mode, which will reduce false positives in CI.

  External URL: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_169089v1/index.html

Participating hosts (42 -> 40)
------------------------------

  Missing    (2): bat-dg2-13 fi-snb-2520m 

Possible new issues
-------------------

  Here are the unknown changes that may have been introduced in Patchwork_169089v1:

### IGT changes ###

#### Possible regressions ####

  * igt@i915_selftest@live@late_gt_pm:
    - fi-bsw-nick:        [PASS][1] -> [ABORT][2] +1 other test abort
   [1]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_18714/fi-bsw-nick/igt@i915_selftest@live@late_gt_pm.html
   [2]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_169089v1/fi-bsw-nick/igt@i915_selftest@live@late_gt_pm.html

  
Known issues
------------

  Here are the changes found in Patchwork_169089v1 that come from known issues:

### IGT changes ###

#### Issues hit ####

  * igt@kms_hdmi_inject@inject-audio:
    - fi-tgl-1115g4:      [PASS][3] -> [FAIL][4] ([i915#16115])
   [3]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_18714/fi-tgl-1115g4/igt@kms_hdmi_inject@inject-audio.html
   [4]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_169089v1/fi-tgl-1115g4/igt@kms_hdmi_inject@inject-audio.html

  
  [i915#16115]: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/16115


Build changes
-------------

  * Linux: CI_DRM_18714 -> Patchwork_169089v1

  CI-20190529: 20190529
  CI_DRM_18714: b2817f6a1517bc9ecdef5229b84e8a44d983de82 @ git://anongit.freedesktop.org/gfx-ci/linux
  IGT_8982: 48befce9e6b0c0d371c4812bfff34a61319f68f1 @ https://gitlab.freedesktop.org/drm/igt-gpu-tools.git
  Patchwork_169089v1: b2817f6a1517bc9ecdef5229b84e8a44d983de82 @ git://anongit.freedesktop.org/gfx-ci/linux

== Logs ==

For more details see: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_169089v1/index.html

[-- Attachment #2: Type: text/html, Size: 3126 bytes --]

Re: ✗ i915.CI.BAT: failure for drm/i915: Return NULL on error in active_instance

[Joonas Lahtinen]

(+ i915-ci-infra)

Below is most definitely unrelated error.

Quoting Patchwork (2026-06-24 13:36:16)
> Patch Details
> 
> Series:  drm/i915: Return NULL on error in active_instance
> URL:     https://patchwork.freedesktop.org/series/169089/
> State:   failure
> Details: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_169089v1/index.html
> 
> CI Bug Log - changes from CI_DRM_18714 -> Patchwork_169089v1
> 
> Summary
> 
> FAILURE
> 
> Serious unknown changes coming with Patchwork_169089v1 absolutely need to be
> verified manually.
> 
> If you think the reported changes have nothing to do with the changes
> introduced in Patchwork_169089v1, please notify your bug team
> (I915-ci-infra@lists.freedesktop.org) to allow them
> to document this new failure mode, which will reduce false positives in CI.
> 
> External URL: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_169089v1/
> index.html
> 
> Participating hosts (42 -> 40)
> 
> Missing (2): bat-dg2-13 fi-snb-2520m
> 
> Possible new issues
> 
> Here are the unknown changes that may have been introduced in
> Patchwork_169089v1:
> 
> IGT changes
> 
> Possible regressions
> 
>   • igt@i915_selftest@live@late_gt_pm:
>       □ fi-bsw-nick: PASS -> ABORT +1 other test abort
> 
> Known issues
> 
> Here are the changes found in Patchwork_169089v1 that come from known issues:
> 
> IGT changes
> 
> Issues hit
> 
>   • igt@kms_hdmi_inject@inject-audio:
>       □ fi-tgl-1115g4: PASS -> FAIL (i915#16115)
> 
> Build changes
> 
>   • Linux: CI_DRM_18714 -> Patchwork_169089v1
> 
> CI-20190529: 20190529
> CI_DRM_18714: b2817f6a1517bc9ecdef5229b84e8a44d983de82 @ git://
> anongit.freedesktop.org/gfx-ci/linux
> IGT_8982: 48befce9e6b0c0d371c4812bfff34a61319f68f1 @ https://
> gitlab.freedesktop.org/drm/igt-gpu-tools.git
> Patchwork_169089v1: b2817f6a1517bc9ecdef5229b84e8a44d983de82 @ git://
> anongit.freedesktop.org/gfx-ci/linux
>

Re: [PATCH] drm/i915: Return NULL on error in active_instance

[Joonas Lahtinen]

Pushed to drm-intel-gt-next, thanks for the reviews.

Regards, Joonas

Re: [PATCH] drm/i915: Return NULL on error in active_instance

[Andi Shyti]

Hi Joonas,

On Wed, Jun 24, 2026 at 02:25:19PM +0300, Joonas Lahtinen wrote:
> Pushed to drm-intel-gt-next, thanks for the reviews.

please, next time:

- Give people more time to review the patch. Only two hours
  passed between posting it and pushing it (during lunch time,
  BTW).

- There were BAT failures. They were unrelated, but so far we
  have generally held back patches until BAT was green, even for
  the most obvious changes.

Thanks,
Andi