Re: [PATCH] drm/amd/amdgpu/amdgpu_ttm: Handle return NULL error from ioremap_nocache

From: Christian KÃnig
Date: Tue Jan 24 2017 - 04:55:49 EST

Am 24.01.2017 um 10:25 schrieb Arvind Yadav:
Here, If ioremap_nocache will fail. It will return NULL.
Kernel can run into a NULL-pointer dereference.
This error check will avoid NULL pointer dereference.

Signed-off-by: Arvind Yadav <arvind.yadav.cs@xxxxxxxxx>

I'm not 100% sure if ioremap_nocache() can actually return NULL on platforms where this matters, but if that's the case the patch looks reasonable on first glance.

So it is Reviewed-by: Christian KÃnig <christian.koenig@xxxxxxx>.


drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
index 8e35c1f..610c88f 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
@@ -552,6 +552,8 @@ static int amdgpu_ttm_io_mem_reserve(struct ttm_bo_device *bdev, struct ttm_mem_
mem->bus.addr =
ioremap_nocache(mem->bus.base + mem->bus.offset,
+ if (!mem->bus.addr)
+ return -ENOMEM;
* Alpha: Use just the bus offset plus