===============================
[ INFO: suspicious RCU usage. ]
3.16.0+ #178 Not tainted
-------------------------------
lib/rhashtable.c:596 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/2/18:
#0: (rcu_callback){......}, at: [<ffffffff810918fd>] rcu_process_callbacks+0x27e/0x4c7
stack backtrace:
CPU: 2 PID: 18 Comm: ksoftirqd/2 Not tainted 3.16.0+ #178
Hardware name: LENOVO 23259H1/23259H1, BIOS G2ET32WW (1.12 ) 05/30/2012
0000000000000001 ffff88011706bb68 ffffffff8143debc 0000000000000000
ffff880117062610 ffff88011706bb98 ffffffff81077515 ffff8800ca041a50
0000000000000004 ffff8800ca386480 ffff8800ca041a00 ffff88011706bbb8
Call Trace:
[<ffffffff8143debc>] dump_stack+0x4e/0x68
[<ffffffff81077515>] lockdep_rcu_suspicious+0xfa/0x103
[<ffffffff81228b1b>] rhashtable_destroy+0x46/0x52
[<ffffffffa06f21a7>] nft_hash_destroy+0x73/0x82 [nft_hash]
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Acked-by: Thomas Graf <tgraf@suug.ch>
---
lib/rhashtable.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
@@ -589,13 +589,13 @@ EXPORT_SYMBOL_GPL(rhashtable_init);
* rhashtable_destroy - destroy hash table
* @ht: the hash table to destroy
*
- * Frees the bucket array.
+ * Frees the bucket array. This function is not rcu safe, therefore the caller
+ * has to make sure that no resizing may happen by unpublishing the hashtable
+ * and waiting for the quiescent cycle before releasing the bucket array.
*/
void rhashtable_destroy(const struct rhashtable *ht)
{
- const struct bucket_table *tbl = rht_dereference(ht->tbl, ht);
-
- bucket_table_free(tbl);
+ bucket_table_free(ht->tbl);
}
EXPORT_SYMBOL_GPL(rhashtable_destroy);