From 2a89ae5d7a7d5845226ed85146140ff4c8788d59 Mon Sep 17 00:00:00 2001 From: Monk Liu Date: Tue, 8 Aug 2017 15:34:20 +0800 Subject: [PATCH] amdgpu: fix race issue between two bo functions(v2) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit there is race issue between two threads on amdgpu_bo_reference and amdgpu_bo_import, this patch tends to fix it by moving the pthread_mutex_lock out of bo_free_internal and move to bo_reference to cover the update_reference part. The mutex_unlock in bo_import should also cover bo refcount increasement. Reviewed-by: Christian König Signed-off-by: Monk Liu Signed-off-by: Alex Deucher --- amdgpu/amdgpu_bo.c | 5 +---- amdgpu/amdgpu_internal.h | 13 +++++++++++-- 2 files changed, 12 insertions(+), 6 deletions(-) diff --git a/amdgpu/amdgpu_bo.c b/amdgpu/amdgpu_bo.c index d2725da8..803fe54c 100644 --- a/amdgpu/amdgpu_bo.c +++ b/amdgpu/amdgpu_bo.c @@ -56,14 +56,12 @@ static void amdgpu_close_kms_handle(amdgpu_device_handle dev, drm_private void amdgpu_bo_free_internal(amdgpu_bo_handle bo) { /* Remove the buffer from the hash tables. */ - pthread_mutex_lock(&bo->dev->bo_table_mutex); util_hash_table_remove(bo->dev->bo_handles, (void*)(uintptr_t)bo->handle); if (bo->flink_name) { util_hash_table_remove(bo->dev->bo_flink_names, (void*)(uintptr_t)bo->flink_name); } - pthread_mutex_unlock(&bo->dev->bo_table_mutex); /* Release CPU access. */ if (bo->cpu_map_count > 0) { @@ -342,10 +340,9 @@ int amdgpu_bo_import(amdgpu_device_handle dev, } if (bo) { - pthread_mutex_unlock(&dev->bo_table_mutex); - /* The buffer already exists, just bump the refcount. */ atomic_inc(&bo->refcount); + pthread_mutex_unlock(&dev->bo_table_mutex); output->buf_handle = bo; output->alloc_size = bo->alloc_size; diff --git a/amdgpu/amdgpu_internal.h b/amdgpu/amdgpu_internal.h index e68246bf..28d1f38f 100644 --- a/amdgpu/amdgpu_internal.h +++ b/amdgpu/amdgpu_internal.h @@ -206,8 +206,17 @@ static inline bool update_references(atomic_t *dst, atomic_t *src) static inline void amdgpu_bo_reference(struct amdgpu_bo **dst, struct amdgpu_bo *src) { - if (update_references(&(*dst)->refcount, &src->refcount)) - amdgpu_bo_free_internal(*dst); + pthread_mutex_t *mlock; + struct amdgpu_bo* bo = *dst; + + assert(bo != NULL); + mlock = &bo->dev->bo_table_mutex; + pthread_mutex_lock(mlock); + + if (update_references(&bo->refcount, src?&src->refcount:NULL)) + amdgpu_bo_free_internal(bo); + + pthread_mutex_unlock(mlock); *dst = src; }