Acked-by: Chunming Zhou <david1.zhou at amd.com> On 2016å¹´10æ??24æ?¥ 02:31, Grazvydas Ignotas wrote: > To free fences, call_rcu() is used, which calls amdgpu_fence_free() > after a grace period. During teardown, there is no guarantee all > callbacks have finished, so amdgpu_fence_slab may be destroyed before > all fences have been freed. If we are lucky, this results in some slab > warnings, if not, we get a crash in one of rcu threads because callback > is called after amdgpu has already been unloaded. > > Fix it with a rcu_barrier(). > > Fixes: b44135351a3a ("drm/amdgpu: RCU protected amdgpu_fence_release") > Signed-off-by: Grazvydas Ignotas <notasas at gmail.com> > --- > drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c > index 3a2e42f..77b34ec 100644 > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c > @@ -68,6 +68,7 @@ int amdgpu_fence_slab_init(void) > > void amdgpu_fence_slab_fini(void) > { > + rcu_barrier(); > kmem_cache_destroy(amdgpu_fence_slab); > } > /*