[PATCH 5.4 13/16] drm/amdgpu: Fix possible NULL dereference in amdgpu_ras_query_error_status_helper()

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

5.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Srinivasan Shanmugam <srinivasan.shanmugam@amd.com>

commit b8d55a90fd55b767c25687747e2b24abd1ef8680 upstream.

Return invalid error code -EINVAL for invalid block id.

Fixes the below:

drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c:1183 amdgpu_ras_query_error_status_helper() error: we previously assumed 'info' could be null (see line 1176)

Suggested-by: Hawking Zhang <Hawking.Zhang@amd.com>
Cc: Tao Zhou <tao.zhou1@amd.com>
Cc: Hawking Zhang <Hawking.Zhang@amd.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Srinivasan Shanmugam <srinivasan.shanmugam@amd.com>
Reviewed-by: Hawking Zhang <Hawking.Zhang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
[Ajay: applied AMDGPU_RAS_BLOCK_COUNT condition to amdgpu_ras_error_query()
       as amdgpu_ras_query_error_status_helper() not present in v5.10, v5.4
       amdgpu_ras_query_error_status_helper() was introduced in 8cc0f5669eb6]
Signed-off-by: Ajay Kaher <ajay.kaher@broadcom.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c
@@ -594,6 +594,9 @@ int amdgpu_ras_error_query(struct amdgpu
 	if (!obj)
 		return -EINVAL;
 
+	if (!info || info->head.block == AMDGPU_RAS_BLOCK_COUNT)
+		return -EINVAL;
+
 	switch (info->head.block) {
 	case AMDGPU_RAS_BLOCK__UMC:
 		if (adev->umc.funcs->query_ras_error_count)