[PATCH v2] drm/amdgpu: skip force complete fences when ring is uninitialized

[Bob Zhou]

uvd ring in uvd_v7_0_sw_init only initializes ring in bare metal case,
so when executing amdgpu_uvd_resume to restore fence seq in SRIOV,
a null pointer dereference will occur. This patch correct this.

Fixes: 043f2271e2d0 ("drm/amdgpu: mark force completed fences with -ECANCELED")

BUG: kernel NULL pointer dereference, address: 0000000000000000
Oops: 0000 [#1] PREEMPT SMP PTI
RIP: 0010:amdgpu_fence_driver_set_error+0x3f/0xc0 [amdgpu]
Call Trace:
 <TASK>
 amdgpu_fence_driver_force_completion+0x18/0x50 [amdgpu]
 amdgpu_uvd_resume+0x1b2/0x380 [amdgpu]
 ? amdgpu_ring_init+0x73c/0x820 [amdgpu]
 uvd_v7_0_sw_init+0x358/0x450 [amdgpu]
 amdgpu_device_init.cold+0x198c/0x1fdf [amdgpu]
 ? pci_bus_read_config_byte+0x40/0x80
 ? pci_read_config_byte+0x27/0x50
 amdgpu_driver_load_kms+0x1a/0x160 [amdgpu]
 amdgpu_pci_probe+0x186/0x3c0 [amdgpu]

Signed-off-by: Bob Zhou <bob.zhou at amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_uvd.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_uvd.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_uvd.c
index b7441654e6fa..70e7e9585d3c 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_uvd.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_uvd.c
@@ -506,7 +506,8 @@ int amdgpu_uvd_resume(struct amdgpu_device *adev)
 			}
 			memset_io(ptr, 0, size);
 			/* to restore uvd fence seq */
-			amdgpu_fence_driver_force_completion(&adev->uvd.inst[i].ring);
+			if (adev->uvd.inst[i].ring.fence_drv.irq_src)
+				amdgpu_fence_driver_force_completion(&adev->uvd.inst[i].ring);
 		}
 	}
 	return 0;
-- 
2.34.1