From c175f5ebb2f4910e2d4f38f794e3973e53baa94e Mon Sep 17 00:00:00 2001 From: Brian Behlendorf Date: Mon, 20 Jun 2022 21:35:38 +0000 Subject: [PATCH] Fix -Wuse-after-free warning in dbuf_destroy() Move the use of the db pointer after it is freed. It's only used as a tag so a dereference would never occur, but there's no reason we can't invert the order to resolve the warning. module/zfs/dbuf.c: In function 'dbuf_destroy': module/zfs/dbuf.c:2953:17: error: pointer 'db' may be used after 'free' [-Werror=use-after-free] Reviewed-by: Ryan Moeller Reviewed-by: Alexander Motin Signed-off-by: Brian Behlendorf Closes #13528 Closes #13575 --- module/zfs/dbuf.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/module/zfs/dbuf.c b/module/zfs/dbuf.c index 71b2b0992..d10e87652 100644 --- a/module/zfs/dbuf.c +++ b/module/zfs/dbuf.c @@ -2941,9 +2941,6 @@ dbuf_destroy(dmu_buf_impl_t *db) ASSERT3U(db->db_caching_status, ==, DB_NO_CACHE); ASSERT(!multilist_link_active(&db->db_cache_link)); - kmem_cache_free(dbuf_kmem_cache, db); - arc_space_return(sizeof (dmu_buf_impl_t), ARC_SPACE_DBUF); - /* * If this dbuf is referenced from an indirect dbuf, * decrement the ref count on the indirect dbuf. @@ -2952,6 +2949,9 @@ dbuf_destroy(dmu_buf_impl_t *db) mutex_enter(&parent->db_mtx); dbuf_rele_and_unlock(parent, db, B_TRUE); } + + kmem_cache_free(dbuf_kmem_cache, db); + arc_space_return(sizeof (dmu_buf_impl_t), ARC_SPACE_DBUF); } /* -- 2.11.4.GIT