From b15c18c51910ec5ef8c506f641f487507e42c79b Mon Sep 17 00:00:00 2001 From: Ilya Maximets Date: Mon, 9 Oct 2023 12:43:21 +0200 Subject: [PATCH] memory: initialize 'fv' in MemoryRegionCache to make Coverity happy Coverity scan reports multiple false-positive "defects" for the following series of actions in virtio.c: MemoryRegionCache indirect_desc_cache; address_space_cache_init_empty(&indirect_desc_cache); address_space_cache_destroy(&indirect_desc_cache); For some reason it's unable to recognize the dependency between 'mrs.mr' and 'fv' and insists that '!mrs.mr' check in address_space_cache_destroy may take a 'false' branch, even though it is explicitly initialized to NULL in the address_space_cache_init_empty(): *** CID 1522371: Memory - illegal accesses (UNINIT) /qemu/hw/virtio/virtio.c: 1627 in virtqueue_split_pop() 1621 } 1622 1623 vq->inuse++; 1624 1625 trace_virtqueue_pop(vq, elem, elem->in_num, elem->out_num); 1626 done: >>> CID 1522371: Memory - illegal accesses (UNINIT) >>> Using uninitialized value "indirect_desc_cache.fv" when >>> calling "address_space_cache_destroy". 1627 address_space_cache_destroy(&indirect_desc_cache); 1628 1629 return elem; 1630 1631 err_undo_map: 1632 virtqueue_undo_map_desc(out_num, in_num, iov); ** CID 1522370: Memory - illegal accesses (UNINIT) Instead of trying to silence these false positive reports in 4 different places, initializing 'fv' as well, as this doesn't result in any noticeable performance impact. Signed-off-by: Ilya Maximets Message-Id: <20231009104322.3085887-1-i.maximets@ovn.org> Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin Reviewed-by: David Hildenbrand Reviewed-by: Stefan Hajnoczi --- include/exec/memory.h | 2 ++ 1 file changed, 2 insertions(+) diff --git a/include/exec/memory.h b/include/exec/memory.h index 653a32ea10..9087d02769 100644 --- a/include/exec/memory.h +++ b/include/exec/memory.h @@ -2793,6 +2793,8 @@ int64_t address_space_cache_init(MemoryRegionCache *cache, static inline void address_space_cache_init_empty(MemoryRegionCache *cache) { cache->mrs.mr = NULL; + /* There is no real need to initialize fv, but it makes Coverity happy. */ + cache->fv = NULL; } /**