[PATCH] drm/amdgpu: fix a bug NULL pointer dereference

[Zhang, Hawking]

[AMD Official Use Only - Internal Distribution Only]

Reviewed-by: Hawking Zhang <Hawking.Zhang at amd.com>

Regards,
Hawking
-----Original Message-----
From: Dennis Li <Dennis.Li at amd.com> 
Sent: Wednesday, February 19, 2020 12:05
To: amd-gfx at lists.freedesktop.org; Deucher, Alexander <Alexander.Deucher at amd.com>; Zhou1, Tao <Tao.Zhou1 at amd.com>; Zhang, Hawking <Hawking.Zhang at amd.com>; Chen, Guchun <Guchun.Chen at amd.com>
Cc: Li, Dennis <Dennis.Li at amd.com>
Subject: [PATCH] drm/amdgpu: fix a bug NULL pointer dereference

check whether the queue of entity is null to avoid null pointer dereference.

Change-Id: I08d56774012cf229ba2fe7a011c1359e8d1e2781
Signed-off-by: Dennis Li <Dennis.Li at amd.com>

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_sdma.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_sdma.c
index 4cc7881f438c..67cca463ddcc 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_sdma.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_sdma.c
@@ -95,6 +95,9 @@ static int amdgpu_vm_sdma_commit(struct amdgpu_vm_update_params *p,
 	int r;
 
 	entity = p->direct ? &p->vm->direct : &p->vm->delayed;
+	if (!entity->rq)
+		return 0;
+
 	ring = container_of(entity->rq->sched, struct amdgpu_ring, sched);
 
 	WARN_ON(ib->length_dw == 0);
--
2.17.1