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* [PATCH] drm/imagination: Move dereference after NULL check in pvr_mmu_backing_page_init()
@ 2023-12-06 14:37 Dan Carpenter
  2023-12-06 14:42 ` Frank Binns
  2023-12-08  9:36 ` (subset) " Maxime Ripard
  0 siblings, 2 replies; 3+ messages in thread
From: Dan Carpenter @ 2023-12-06 14:37 UTC (permalink / raw)
  To: Donald Robson
  Cc: Frank Binns, Matt Coster, Maarten Lankhorst, Maxime Ripard,
	Thomas Zimmermann, David Airlie, Daniel Vetter, Sarah Walker,
	dri-devel, linux-kernel, kernel-janitors

This code dereferences "page->pvr_dev" and then checked for NULL on the
next line.  Re-order it to avoid a potential NULL pointer dereference.

Fixes: ff5f643de0bf ("drm/imagination: Add GEM and VM related code")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
---
 drivers/gpu/drm/imagination/pvr_mmu.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/imagination/pvr_mmu.c b/drivers/gpu/drm/imagination/pvr_mmu.c
index c8562bfc0dcd..4fe70610ed94 100644
--- a/drivers/gpu/drm/imagination/pvr_mmu.c
+++ b/drivers/gpu/drm/imagination/pvr_mmu.c
@@ -316,12 +316,14 @@ pvr_mmu_backing_page_init(struct pvr_mmu_backing_page *page,
 static void
 pvr_mmu_backing_page_fini(struct pvr_mmu_backing_page *page)
 {
-	struct device *dev = from_pvr_device(page->pvr_dev)->dev;
+	struct device *dev;
 
 	/* Do nothing if no allocation is present. */
 	if (!page->pvr_dev)
 		return;
 
+	dev = from_pvr_device(page->pvr_dev)->dev;
+
 	dma_unmap_page(dev, page->dma_addr, PVR_MMU_BACKING_PAGE_SIZE,
 		       DMA_TO_DEVICE);
 
-- 
2.42.0


^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [PATCH] drm/imagination: Move dereference after NULL check in pvr_mmu_backing_page_init()
  2023-12-06 14:37 [PATCH] drm/imagination: Move dereference after NULL check in pvr_mmu_backing_page_init() Dan Carpenter
@ 2023-12-06 14:42 ` Frank Binns
  2023-12-08  9:36 ` (subset) " Maxime Ripard
  1 sibling, 0 replies; 3+ messages in thread
From: Frank Binns @ 2023-12-06 14:42 UTC (permalink / raw)
  To: Donald Robson, dan.carpenter
  Cc: kernel-janitors, tzimmermann, Matt Coster, dri-devel, airlied,
	linux-kernel, Sarah Walker, maarten.lankhorst, daniel, mripard

Hi Dan,

Thank you for the patch.

On Wed, 2023-12-06 at 17:37 +0300, Dan Carpenter wrote:
> This code dereferences "page->pvr_dev" and then checked for NULL on the
> next line.  Re-order it to avoid a potential NULL pointer dereference.
> 
> Fixes: ff5f643de0bf ("drm/imagination: Add GEM and VM related code")
> Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>

Reviewed-by: Frank Binns <frank.binns@imgtec.com>

> ---
>  drivers/gpu/drm/imagination/pvr_mmu.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/imagination/pvr_mmu.c b/drivers/gpu/drm/imagination/pvr_mmu.c
> index c8562bfc0dcd..4fe70610ed94 100644
> --- a/drivers/gpu/drm/imagination/pvr_mmu.c
> +++ b/drivers/gpu/drm/imagination/pvr_mmu.c
> @@ -316,12 +316,14 @@ pvr_mmu_backing_page_init(struct pvr_mmu_backing_page *page,
>  static void
>  pvr_mmu_backing_page_fini(struct pvr_mmu_backing_page *page)
>  {
> -	struct device *dev = from_pvr_device(page->pvr_dev)->dev;
> +	struct device *dev;
>  
>  	/* Do nothing if no allocation is present. */
>  	if (!page->pvr_dev)
>  		return;
>  
> +	dev = from_pvr_device(page->pvr_dev)->dev;
> +
>  	dma_unmap_page(dev, page->dma_addr, PVR_MMU_BACKING_PAGE_SIZE,
>  		       DMA_TO_DEVICE);
>  

^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: (subset) [PATCH] drm/imagination: Move dereference after NULL check in pvr_mmu_backing_page_init()
  2023-12-06 14:37 [PATCH] drm/imagination: Move dereference after NULL check in pvr_mmu_backing_page_init() Dan Carpenter
  2023-12-06 14:42 ` Frank Binns
@ 2023-12-08  9:36 ` Maxime Ripard
  1 sibling, 0 replies; 3+ messages in thread
From: Maxime Ripard @ 2023-12-08  9:36 UTC (permalink / raw)
  To: Donald Robson, Dan Carpenter
  Cc: Frank Binns, Matt Coster, Maarten Lankhorst, Thomas Zimmermann,
	David Airlie, Daniel Vetter, Sarah Walker, dri-devel,
	linux-kernel, kernel-janitors

On Wed, 06 Dec 2023 17:37:24 +0300, Dan Carpenter wrote:
> This code dereferences "page->pvr_dev" and then checked for NULL on the
> next line.  Re-order it to avoid a potential NULL pointer dereference.
> 
> 

Applied to drm/drm-misc (drm-misc-next).

Thanks!
Maxime


^ permalink raw reply	[flat|nested] 3+ messages in thread

end of thread, other threads:[~2023-12-08  9:36 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2023-12-06 14:37 [PATCH] drm/imagination: Move dereference after NULL check in pvr_mmu_backing_page_init() Dan Carpenter
2023-12-06 14:42 ` Frank Binns
2023-12-08  9:36 ` (subset) " Maxime Ripard

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