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

[Arvind Yadav <arvind.yadav.cs@gmail.com>]

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@gmail.com>
---
 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,
 						mem->bus.size);
+		if (!mem->bus.addr)
+			return -ENOMEM;
 
 		/*
 		 * Alpha: Use just the bus offset plus
-- 
1.9.1