From 39f390167e9ca73c009d3c8e2d6c3b4286b02ab6 Mon Sep 17 00:00:00 2001 From: Pablo Neira Ayuso Date: Mon, 1 Sep 2014 11:09:35 +0200 Subject: netfilter: nft_hash: no need for rcu in the hash set destroy path The sets are released from the rcu callback, after the rule is removed from the chain list, which implies that nfnetlink cannot update the hashes (thus, no resizing may occur) and no packets are walking on the set anymore. This resolves a lockdep splat in the nft_hash_destroy() path since the nfnl mutex is not held there. =============================== [ INFO: suspicious RCU usage. ] 3.16.0-rc2+ #168 Not tainted ------------------------------- net/netfilter/nft_hash.c:362 suspicious rcu_dereference_protected() usage! other info that might help us debug this: rcu_scheduler_active = 1, debug_locks = 1 1 lock held by ksoftirqd/0/3: #0: (rcu_callback){......}, at: [] rcu_process_callbacks+0x27e/0x4c7 stack backtrace: CPU: 0 PID: 3 Comm: ksoftirqd/0 Not tainted 3.16.0-rc2+ #168 Hardware name: LENOVO 23259H1/23259H1, BIOS G2ET32WW (1.12 ) 05/30/2012 0000000000000001 ffff88011769bb98 ffffffff8142c922 0000000000000006 ffff880117694090 ffff88011769bbc8 ffffffff8107c3ff ffff8800cba52400 ffff8800c476bea8 ffff8800c476bea8 ffff8800cba52400 ffff88011769bc08 Call Trace: [] dump_stack+0x4e/0x68 [] lockdep_rcu_suspicious+0xfa/0x103 [] nft_hash_destroy+0x50/0x137 [nft_hash] [] nft_set_destroy+0x11/0x2a [nf_tables] Signed-off-by: Pablo Neira Ayuso Acked-by: Thomas Graf --- net/netfilter/nft_hash.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) (limited to 'net/netfilter/nft_hash.c') diff --git a/net/netfilter/nft_hash.c b/net/netfilter/nft_hash.c index 28fb8f38e6ba..8892b7b6184a 100644 --- a/net/netfilter/nft_hash.c +++ b/net/netfilter/nft_hash.c @@ -180,15 +180,17 @@ static int nft_hash_init(const struct nft_set *set, static void nft_hash_destroy(const struct nft_set *set) { const struct rhashtable *priv = nft_set_priv(set); - const struct bucket_table *tbl; + const struct bucket_table *tbl = priv->tbl; struct nft_hash_elem *he, *next; unsigned int i; - tbl = rht_dereference(priv->tbl, priv); - for (i = 0; i < tbl->size; i++) - rht_for_each_entry_safe(he, next, tbl->buckets[i], priv, node) + for (i = 0; i < tbl->size; i++) { + for (he = rht_entry(tbl->buckets[i], struct nft_hash_elem, node); + he != NULL; he = next) { + next = rht_entry(he->node.next, struct nft_hash_elem, node); nft_hash_elem_destroy(set, he); - + } + } rhashtable_destroy(priv); } -- cgit