[PATCH] 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: 043f2271e2d0a ("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_fence.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c
index c694b41f6461..d2c5484309a6 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c
@@ -723,6 +723,8 @@ void amdgpu_fence_driver_set_error(struct amdgpu_ring *ring, int error)
  */
 void amdgpu_fence_driver_force_completion(struct amdgpu_ring *ring)
 {
+	if (ring->fence_drv.irq_src)
+		return;
 	amdgpu_fence_driver_set_error(ring, -ECANCELED);
 	amdgpu_fence_write(ring, ring->fence_drv.sync_seq);
 	amdgpu_fence_process(ring);
-- 
2.34.1