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drm/amdgpu: fix a potential deadlock in amdgpu_bo_create_restricted()

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When ttm_bo_init() fails, the reservation mutex should be unlocked.

In debug build, the kernel reported "possible recursive locking
detected" in this codepath. For debugging purposes, I also added
a "WARN_ON(ww_mutex_is_locked())" when ttm_bo_init() fails and the
mutex was locked as expected.

This should fix (random) GPU hangs. The easy way to reproduce the
issue is to change the "Super Sampling" option from 1.0 to 2.0 in
Hitman. It will create a huge buffer, evict a bunch of buffers
(around ~5k) and deadlock.

This regression has been introduced pretty recently.

v2: only release the mutex if resv is NULL

Fixes: 12a852219583 ("drm/amdgpu: improve AMDGPU_GEM_CREATE_VRAM_CLEARED handling (v2)")
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
This commit is contained in:
Samuel Pitoiset 2017-02-09 11:33:36 +01:00 committed by Alex Deucher
parent a52d120f62
commit 38fc4856ad
1 changed files with 4 additions and 1 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

5
drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
View file

@ -405,8 +405,11 @@ int amdgpu_bo_create_restricted(struct amdgpu_device *adev,
&bo->placement, page_align, !kernel, NULL,
acc_size, sg, resv ? resv : &bo->tbo.ttm_resv,
&amdgpu_ttm_bo_destroy);
if (unlikely(r != 0))
if (unlikely(r != 0)) {
if (!resv)
ww_mutex_unlock(&bo->tbo.resv->lock);
return r;
}
bo->tbo.priority = ilog2(bo->tbo.num_pages);
if (kernel)