From ec9d169eb33e6a65db641792821cc6a259ed9362 Mon Sep 17 00:00:00 2001 From: David Ahern Date: Mon, 2 Aug 2021 08:29:26 -0600 Subject: [PATCH net-next] ipv4: Fix refcount warning for new fib_info Ioana reported a refcount warning when booting over NFS: [ 5.042532] ------------[ cut here ]------------ [ 5.047184] refcount_t: addition on 0; use-after-free. [ 5.052324] WARNING: CPU: 7 PID: 1 at lib/refcount.c:25 refcount_warn_saturate+0xa4/0x150 ... [ 5.167201] Call trace: [ 5.169635] refcount_warn_saturate+0xa4/0x150 [ 5.174067] fib_create_info+0xc00/0xc90 [ 5.177982] fib_table_insert+0x8c/0x620 [ 5.181893] fib_magic.isra.0+0x110/0x11c [ 5.185891] fib_add_ifaddr+0xb8/0x190 [ 5.189629] fib_inetaddr_event+0x8c/0x140 fib_treeref needs to be set after kzalloc. The old code had a ++ which led to the confusion when the int was replaced by a refcount_t. Fixes: 79976892f7ea ("net: convert fib_treeref from int to refcount_t") Signed-off-by: David Ahern Reported-by: Ioana Ciornei Cc: Yajun Deng --- net/ipv4/fib_semantics.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/ipv4/fib_semantics.c b/net/ipv4/fib_semantics.c index fa19f4cdf3a4..f29feb7772da 100644 --- a/net/ipv4/fib_semantics.c +++ b/net/ipv4/fib_semantics.c @@ -1551,7 +1551,7 @@ struct fib_info *fib_create_info(struct fib_config *cfg, return ofi; } - refcount_inc(&fi->fib_treeref); + refcount_set(&fi->fib_treeref, 1); refcount_set(&fi->fib_clntref, 1); spin_lock_bh(&fib_info_lock); hlist_add_head(&fi->fib_hash, -- 2.24.3 (Apple Git-128)