diff mbox series

[v2] dma-buf: fix an error pointer vs NULL bug

Message ID b09f1996-3838-4fa2-9193-832b68262e43@moroto.mountain
State Accepted
Commit 00ae1491f970acc454be0df63f50942d94825860
Headers show
Series [v2] dma-buf: fix an error pointer vs NULL bug | expand

Commit Message

Dan Carpenter July 6, 2023, 12:37 p.m. UTC
Smatch detected potential error pointer dereference.

    drivers/gpu/drm/drm_syncobj.c:888 drm_syncobj_transfer_to_timeline()
    error: 'fence' dereferencing possible ERR_PTR()

The error pointer comes from dma_fence_allocate_private_stub().  One
caller expected error pointers and one expected NULL pointers.  Change
it to return NULL and update the caller which expected error pointers,
drm_syncobj_assign_null_handle(), to check for NULL instead.

Fixes: f781f661e8c9 ("dma-buf: keep the signaling time of merged fences v3")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
---
v2: Fix it in dma_fence_allocate_private_stub() instead of
   __dma_fence_unwrap_merge().


 drivers/dma-buf/dma-fence.c   | 2 +-
 drivers/gpu/drm/drm_syncobj.c | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

Comments

Christian König July 6, 2023, 12:54 p.m. UTC | #1
Am 06.07.23 um 14:37 schrieb Dan Carpenter:
> Smatch detected potential error pointer dereference.
>
>      drivers/gpu/drm/drm_syncobj.c:888 drm_syncobj_transfer_to_timeline()
>      error: 'fence' dereferencing possible ERR_PTR()
>
> The error pointer comes from dma_fence_allocate_private_stub().  One
> caller expected error pointers and one expected NULL pointers.  Change
> it to return NULL and update the caller which expected error pointers,
> drm_syncobj_assign_null_handle(), to check for NULL instead.
>
> Fixes: f781f661e8c9 ("dma-buf: keep the signaling time of merged fences v3")
> Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>

Reviewed-by: Christian König <christian.koenig@amd.com>

Should I push that one to drm-misc-fixes?

Regards,
Christian.

> ---
> v2: Fix it in dma_fence_allocate_private_stub() instead of
>     __dma_fence_unwrap_merge().
>
>
>   drivers/dma-buf/dma-fence.c   | 2 +-
>   drivers/gpu/drm/drm_syncobj.c | 4 ++--
>   2 files changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/dma-buf/dma-fence.c b/drivers/dma-buf/dma-fence.c
> index ad076f208760..8aa8f8cb7071 100644
> --- a/drivers/dma-buf/dma-fence.c
> +++ b/drivers/dma-buf/dma-fence.c
> @@ -160,7 +160,7 @@ struct dma_fence *dma_fence_allocate_private_stub(ktime_t timestamp)
>   
>   	fence = kzalloc(sizeof(*fence), GFP_KERNEL);
>   	if (fence == NULL)
> -		return ERR_PTR(-ENOMEM);
> +		return NULL;
>   
>   	dma_fence_init(fence,
>   		       &dma_fence_stub_ops,
> diff --git a/drivers/gpu/drm/drm_syncobj.c b/drivers/gpu/drm/drm_syncobj.c
> index 04589a35eb09..e592c5da70ce 100644
> --- a/drivers/gpu/drm/drm_syncobj.c
> +++ b/drivers/gpu/drm/drm_syncobj.c
> @@ -355,8 +355,8 @@ static int drm_syncobj_assign_null_handle(struct drm_syncobj *syncobj)
>   {
>   	struct dma_fence *fence = dma_fence_allocate_private_stub(ktime_get());
>   
> -	if (IS_ERR(fence))
> -		return PTR_ERR(fence);
> +	if (!fence)
> +		return -ENOMEM;
>   
>   	drm_syncobj_replace_fence(syncobj, fence);
>   	dma_fence_put(fence);
Sumit Semwal July 6, 2023, 2:13 p.m. UTC | #2
On Thu, 6 Jul 2023 at 18:24, Christian König <christian.koenig@amd.com> wrote:
>
> Am 06.07.23 um 14:37 schrieb Dan Carpenter:
> > Smatch detected potential error pointer dereference.
> >
> >      drivers/gpu/drm/drm_syncobj.c:888 drm_syncobj_transfer_to_timeline()
> >      error: 'fence' dereferencing possible ERR_PTR()
> >
> > The error pointer comes from dma_fence_allocate_private_stub().  One
> > caller expected error pointers and one expected NULL pointers.  Change
> > it to return NULL and update the caller which expected error pointers,
> > drm_syncobj_assign_null_handle(), to check for NULL instead.
> >
> > Fixes: f781f661e8c9 ("dma-buf: keep the signaling time of merged fences v3")
> > Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
>
Thanks for catching this!
> Reviewed-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Sumit Semwal <sumit.semwal@linaro.org>
>
> Should I push that one to drm-misc-fixes?
If you haven't pushed already, I can push it now.
>
> Regards,
> Christian.

Best,
Sumit.
>
> > ---
> > v2: Fix it in dma_fence_allocate_private_stub() instead of
> >     __dma_fence_unwrap_merge().
> >
> >
> >   drivers/dma-buf/dma-fence.c   | 2 +-
> >   drivers/gpu/drm/drm_syncobj.c | 4 ++--
> >   2 files changed, 3 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/dma-buf/dma-fence.c b/drivers/dma-buf/dma-fence.c
> > index ad076f208760..8aa8f8cb7071 100644
> > --- a/drivers/dma-buf/dma-fence.c
> > +++ b/drivers/dma-buf/dma-fence.c
> > @@ -160,7 +160,7 @@ struct dma_fence *dma_fence_allocate_private_stub(ktime_t timestamp)
> >
> >       fence = kzalloc(sizeof(*fence), GFP_KERNEL);
> >       if (fence == NULL)
> > -             return ERR_PTR(-ENOMEM);
> > +             return NULL;
> >
> >       dma_fence_init(fence,
> >                      &dma_fence_stub_ops,
> > diff --git a/drivers/gpu/drm/drm_syncobj.c b/drivers/gpu/drm/drm_syncobj.c
> > index 04589a35eb09..e592c5da70ce 100644
> > --- a/drivers/gpu/drm/drm_syncobj.c
> > +++ b/drivers/gpu/drm/drm_syncobj.c
> > @@ -355,8 +355,8 @@ static int drm_syncobj_assign_null_handle(struct drm_syncobj *syncobj)
> >   {
> >       struct dma_fence *fence = dma_fence_allocate_private_stub(ktime_get());
> >
> > -     if (IS_ERR(fence))
> > -             return PTR_ERR(fence);
> > +     if (!fence)
> > +             return -ENOMEM;
> >
> >       drm_syncobj_replace_fence(syncobj, fence);
> >       dma_fence_put(fence);
>
diff mbox series

Patch

diff --git a/drivers/dma-buf/dma-fence.c b/drivers/dma-buf/dma-fence.c
index ad076f208760..8aa8f8cb7071 100644
--- a/drivers/dma-buf/dma-fence.c
+++ b/drivers/dma-buf/dma-fence.c
@@ -160,7 +160,7 @@  struct dma_fence *dma_fence_allocate_private_stub(ktime_t timestamp)
 
 	fence = kzalloc(sizeof(*fence), GFP_KERNEL);
 	if (fence == NULL)
-		return ERR_PTR(-ENOMEM);
+		return NULL;
 
 	dma_fence_init(fence,
 		       &dma_fence_stub_ops,
diff --git a/drivers/gpu/drm/drm_syncobj.c b/drivers/gpu/drm/drm_syncobj.c
index 04589a35eb09..e592c5da70ce 100644
--- a/drivers/gpu/drm/drm_syncobj.c
+++ b/drivers/gpu/drm/drm_syncobj.c
@@ -355,8 +355,8 @@  static int drm_syncobj_assign_null_handle(struct drm_syncobj *syncobj)
 {
 	struct dma_fence *fence = dma_fence_allocate_private_stub(ktime_get());
 
-	if (IS_ERR(fence))
-		return PTR_ERR(fence);
+	if (!fence)
+		return -ENOMEM;
 
 	drm_syncobj_replace_fence(syncobj, fence);
 	dma_fence_put(fence);