[PATCH 5.15.y] drm/amdgpu: fix a memory leak in fence cleanup when unloading

[Sasha Levin <sashal@kernel.org>]

From: Alex Deucher <alexander.deucher@amd.com>

[ Upstream commit 7838fb5f119191403560eca2e23613380c0e425e ]

Commit b61badd20b44 ("drm/amdgpu: fix usage slab after free")
reordered when amdgpu_fence_driver_sw_fini() was called after
that patch, amdgpu_fence_driver_sw_fini() effectively became
a no-op as the sched entities we never freed because the
ring pointers were already set to NULL.  Remove the NULL
setting.

Reported-by: Lin.Cao <lincao12@amd.com>
Cc: Vitaly Prosyak <vitaly.prosyak@amd.com>
Cc: Christian König <christian.koenig@amd.com>
Fixes: b61badd20b44 ("drm/amdgpu: fix usage slab after free")
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit a525fa37aac36c4591cc8b07ae8957862415fbd5)
Cc: stable@vger.kernel.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_ring.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.c
index de05b7f864f2c..ab10addf130c3 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.c
@@ -302,8 +302,6 @@ void amdgpu_ring_fini(struct amdgpu_ring *ring)
 	dma_fence_put(ring->vmid_wait);
 	ring->vmid_wait = NULL;
 	ring->me = 0;
-
-	ring->adev->rings[ring->idx] = NULL;
 }
 
 /**
-- 
2.51.0