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drm/ttm: Always and only destroy bo->ttm_resv in ttm_bo_release_list 

Fixes a use-after-free due to a race condition in
ttm_bo_cleanup_refs_and_unlock, which allows one task to reserve a BO
and destroy its ttm_resv while another task is waiting for it to signal
in reservation_object_wait_timeout_rcu.

v2:
* Always initialize bo->ttm_resv in ttm_bo_init_reserved
 (Christian König)

Fixes: 0d2bd2ae04 "drm/ttm: fix memory leak while individualizing BOs"
Reviewed-by: Chunming Zhou <david1.zhou@amd.com> # v1
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Michel Dänzer <michel.daenzer@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
hifive-unleashed-5.1
Michel Dänzer 2017-11-03 16:00:35 +01:00 committed by Alex Deucher
parent 37c5f2c99a
commit e1fc12c5d9
1 changed files with 4 additions and 12 deletions
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16
drivers/gpu/drm/ttm/ttm_bo.c
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@ -150,8 +150,7 @@ static void ttm_bo_release_list(struct kref *list_kref)
ttm_tt_destroy(bo->ttm);
atomic_dec(&bo->glob->bo_count);
dma_fence_put(bo->moving);
if (bo->resv == &bo->ttm_resv)
reservation_object_fini(&bo->ttm_resv);
reservation_object_fini(&bo->ttm_resv);
mutex_destroy(&bo->wu_mutex);
if (bo->destroy)
bo->destroy(bo);
@ -402,14 +401,11 @@ static int ttm_bo_individualize_resv(struct ttm_buffer_object *bo)
if (bo->resv == &bo->ttm_resv)
return 0;
reservation_object_init(&bo->ttm_resv);
BUG_ON(!reservation_object_trylock(&bo->ttm_resv));
r = reservation_object_copy_fences(&bo->ttm_resv, bo->resv);
if (r) {
if (r)
reservation_object_unlock(&bo->ttm_resv);
reservation_object_fini(&bo->ttm_resv);
}
return r;
}
@ -457,10 +453,8 @@ static void ttm_bo_cleanup_refs_or_queue(struct ttm_buffer_object *bo)
if (reservation_object_test_signaled_rcu(&bo->ttm_resv, true)) {
ttm_bo_del_from_lru(bo);
spin_unlock(&glob->lru_lock);
if (bo->resv != &bo->ttm_resv) {
if (bo->resv != &bo->ttm_resv)
reservation_object_unlock(&bo->ttm_resv);
reservation_object_fini(&bo->ttm_resv);
}
ttm_bo_cleanup_memtype_use(bo);
return;
@ -560,8 +554,6 @@ static int ttm_bo_cleanup_refs_and_unlock(struct ttm_buffer_object *bo,
}
ttm_bo_del_from_lru(bo);
if (!list_empty(&bo->ddestroy) && (bo->resv != &bo->ttm_resv))
reservation_object_fini(&bo->ttm_resv);
list_del_init(&bo->ddestroy);
kref_put(&bo->list_kref, ttm_bo_ref_bug);
@ -1210,8 +1202,8 @@ int ttm_bo_init_reserved(struct ttm_bo_device *bdev,
lockdep_assert_held(&bo->resv->lock.base);
} else {
bo->resv = &bo->ttm_resv;
reservation_object_init(&bo->ttm_resv);
}
reservation_object_init(&bo->ttm_resv);
atomic_inc(&bo->glob->bo_count);
drm_vma_node_reset(&bo->vma_node);
bo->priority = 0;