Ping ...... > -----Original Message----- > From: Emily Deng [mailto:Emily.Deng at amd.com] > Sent: Monday, May 21, 2018 4:09 PM > To: amd-gfx at lists.freedesktop.org > Cc: Deng, Emily <Emily.Deng at amd.com> > Subject: [PATCH] drm/amdgpu: add rcu_barrier after entity fini > > To free the fence from the amdgpu_fence_slab, need twice call_rcu, to > avoid the amdgpu_fence_slab_fini call > kmem_cache_destroy(amdgpu_fence_slab) before > kmem_cache_free(amdgpu_fence_slab, fence), add rcu_barrier after > drm_sched_entity_fini. > > The kmem_cache_free(amdgpu_fence_slab, fence)'s call trace as below: > 1.drm_sched_entity_fini -> > drm_sched_entity_cleanup -> > dma_fence_put(entity->last_scheduled) -> > drm_sched_fence_release_finished -> > drm_sched_fence_release_scheduled -> call_rcu(&fence->finished.rcu, > drm_sched_fence_free) > > 2.drm_sched_fence_free -> > dma_fence_put(fence->parent) -> > amdgpu_fence_release -> > call_rcu(&f->rcu, amdgpu_fence_free) -> > kmem_cache_free(amdgpu_fence_slab, fence); > > v2:put the barrier before the kmem_cache_destroy v3:put the > dma_fence_put(fence->parent) before call_rcu in > drm_sched_fence_release_scheduled > > Change-Id: I8dcadd3372f97e72461bf46b41cc26d90f09b8df > Signed-off-by: Emily Deng <Emily.Deng at amd.com> > --- > drivers/gpu/drm/scheduler/sched_fence.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/scheduler/sched_fence.c > b/drivers/gpu/drm/scheduler/sched_fence.c > index 786b47f..df44616 100644 > --- a/drivers/gpu/drm/scheduler/sched_fence.c > +++ b/drivers/gpu/drm/scheduler/sched_fence.c > @@ -98,7 +98,6 @@ static void drm_sched_fence_free(struct rcu_head *rcu) > struct dma_fence *f = container_of(rcu, struct dma_fence, rcu); > struct drm_sched_fence *fence = to_drm_sched_fence(f); > > - dma_fence_put(fence->parent); > kmem_cache_free(sched_fence_slab, fence); } > > @@ -114,6 +113,7 @@ static void > drm_sched_fence_release_scheduled(struct dma_fence *f) { > struct drm_sched_fence *fence = to_drm_sched_fence(f); > > + dma_fence_put(fence->parent); > call_rcu(&fence->finished.rcu, drm_sched_fence_free); } > > -- > 2.7.4
