Re: [PATCH v2 03/11] drm/tegra: vic: Fix DMA API misuse

[Thierry Reding]

On Fri, Dec 10, 2021 at 05:54:44PM +, Robin Murphy wrote:
> Upon failure, dma_alloc_coherent() returns NULL. If that does happen,
> passing some uninitialised stack contents to dma_mapping_error() - which
> belongs to a different API in the first place - has precious little
> chance of detecting it.
> 
> Also include the correct header, because the fragile transitive
> inclusion currently providing it is going to break soon.
> 
> Fixes: 20e7dce255e9 ("drm/tegra: Remove memory allocation from Falcon 
> library")
> CC: Thierry Reding 
> CC: Mikko Perttunen 
> CC: dri-de...@lists.freedesktop.org
> Signed-off-by: Robin Murphy 
> 
> ---
> 
> It also doesn't appear to handle failure of the tegra_drm_alloc() path
> either, but that's a loose thread I have no desire to pull on... ;)
> 
> v2: Resend as part of the series, originally posted separately here:
> 
> https://lore.kernel.org/dri-devel/2703882439344010e33bf21ecd63cf9e5e6dc00d.1637781007.git.robin.mur...@arm.com/
> 
>  drivers/gpu/drm/tegra/vic.c | 7 +++
>  1 file changed, 3 insertions(+), 4 deletions(-)

Applied, thanks. I've also fixed up the missing failure handling for
tegra_drm_alloc(), which was actually quite trivial to do.

Thierry


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Re: [PATCH v2 03/11] drm/tegra: vic: Fix DMA API misuse

[Christoph Hellwig]

Looks good,

Reviewed-by: Christoph Hellwig 
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[PATCH v2 03/11] drm/tegra: vic: Fix DMA API misuse

[Robin Murphy]

Upon failure, dma_alloc_coherent() returns NULL. If that does happen,
passing some uninitialised stack contents to dma_mapping_error() - which
belongs to a different API in the first place - has precious little
chance of detecting it.

Also include the correct header, because the fragile transitive
inclusion currently providing it is going to break soon.

Fixes: 20e7dce255e9 ("drm/tegra: Remove memory allocation from Falcon library")
CC: Thierry Reding 
CC: Mikko Perttunen 
CC: dri-de...@lists.freedesktop.org
Signed-off-by: Robin Murphy 

---

It also doesn't appear to handle failure of the tegra_drm_alloc() path
either, but that's a loose thread I have no desire to pull on... ;)

v2: Resend as part of the series, originally posted separately here:

https://lore.kernel.org/dri-devel/2703882439344010e33bf21ecd63cf9e5e6dc00d.1637781007.git.robin.mur...@arm.com/

 drivers/gpu/drm/tegra/vic.c | 7 +++
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/tegra/vic.c b/drivers/gpu/drm/tegra/vic.c
index c02010ff2b7f..da4af5371991 100644
--- a/drivers/gpu/drm/tegra/vic.c
+++ b/drivers/gpu/drm/tegra/vic.c
@@ -5,6 +5,7 @@
 
 #include 
 #include 
+#include 
 #include 
 #include 
 #include 
@@ -232,10 +233,8 @@ static int vic_load_firmware(struct vic *vic)
 
if (!client->group) {
virt = dma_alloc_coherent(vic->dev, size, , GFP_KERNEL);
-
-   err = dma_mapping_error(vic->dev, iova);
-   if (err < 0)
-   return err;
+   if (!virt)
+   return -ENOMEM;
} else {
virt = tegra_drm_alloc(tegra, size, );
}
-- 
2.28.0.dirty

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