From: Nicolai Hähnle Date: Fri, 29 Jun 2018 11:23:25 +0000 (+0200) Subject: drm/amdgpu: fix user fence write race condition X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=c660f40b711980b42d8beac4b395a10645b20d5d;p=linux.git drm/amdgpu: fix user fence write race condition 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 Reviewed-by: Alex Deucher Signed-off-by: Alex Deucher 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 f70eeed9ed76f..7aaa263ad8c7e 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);