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authorPablo Neira Ayuso <pablo@netfilter.org>2014-09-01 11:09:35 +0200
committerPablo Neira Ayuso <pablo@netfilter.org>2014-09-03 10:57:06 +0200
commit39f390167e9ca73c009d3c8e2d6c3b4286b02ab6 (patch)
tree143bf3f5a0819a84f9594fbd5aceb0dc60510ca9 /net
parentbec6bfb2437f4676dbaaacba6019e9dafef18962 (diff)
downloadop-kernel-dev-39f390167e9ca73c009d3c8e2d6c3b4286b02ab6.zip
op-kernel-dev-39f390167e9ca73c009d3c8e2d6c3b4286b02ab6.tar.gz
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: [<ffffffff81096393>] 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: [<ffffffff8142c922>] dump_stack+0x4e/0x68 [<ffffffff8107c3ff>] lockdep_rcu_suspicious+0xfa/0x103 [<ffffffffa079931e>] nft_hash_destroy+0x50/0x137 [nft_hash] [<ffffffffa078cd57>] nft_set_destroy+0x11/0x2a [nf_tables] Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> Acked-by: Thomas Graf <tgraf@suug.ch>
Diffstat (limited to 'net')
-rw-r--r--net/netfilter/nft_hash.c12
1 files changed, 7 insertions, 5 deletions
diff --git a/net/netfilter/nft_hash.c b/net/netfilter/nft_hash.c
index 28fb8f3..8892b7b 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);
}
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