The patch below does not apply to the 4.17-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From c660f40b711980b42d8beac4b395a10645b20d5d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Nicolai=20H=C3=A4hnle?= nicolai.haehnle@amd.com Date: Fri, 29 Jun 2018 13:23:25 +0200 Subject: [PATCH] drm/amdgpu: fix user fence write race condition MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit
The buffer object backing the user fence is reserved using the non-user fence, i.e., as soon as the non-user fence is signaled, the user fence buffer object can be moved or even destroyed.
Therefore, emit the user fence first.
Both fences have the same cache invalidation behavior, so this should have no user-visible effect.
Signed-off-by: Nicolai Hähnle nicolai.haehnle@amd.com Reviewed-by: Alex Deucher alexander.deucher@amd.com Signed-off-by: Alex Deucher alexander.deucher@amd.com Cc: stable@vger.kernel.org
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ib.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ib.c index f70eeed9ed76..7aaa263ad8c7 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ib.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ib.c @@ -231,6 +231,12 @@ int amdgpu_ib_schedule(struct amdgpu_ring *ring, unsigned num_ibs, if (ib->flags & AMDGPU_IB_FLAG_TC_WB_NOT_INVALIDATE) fence_flags |= AMDGPU_FENCE_FLAG_TC_WB_ONLY;
+ /* wrap the last IB with fence */ + if (job && job->uf_addr) { + amdgpu_ring_emit_fence(ring, job->uf_addr, job->uf_sequence, + fence_flags | AMDGPU_FENCE_FLAG_64BIT); + } + r = amdgpu_fence_emit(ring, f, fence_flags); if (r) { dev_err(adev->dev, "failed to emit fence (%d)\n", r); @@ -243,12 +249,6 @@ int amdgpu_ib_schedule(struct amdgpu_ring *ring, unsigned num_ibs, if (ring->funcs->insert_end) ring->funcs->insert_end(ring);
- /* wrap the last IB with fence */ - if (job && job->uf_addr) { - amdgpu_ring_emit_fence(ring, job->uf_addr, job->uf_sequence, - fence_flags | AMDGPU_FENCE_FLAG_64BIT); - } - if (patch_offset != ~0 && ring->funcs->patch_cond_exec) amdgpu_ring_patch_cond_exec(ring, patch_offset);