From: Johannes Berg Date: Tue, 19 Mar 2024 08:10:22 +0000 (+0200) Subject: wifi: iwlwifi: read txq->read_ptr under lock X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=c2ace6300600c634553657785dfe5ea0ed688ac2;p=linux.git wifi: iwlwifi: read txq->read_ptr under lock If we read txq->read_ptr without lock, we can read the same value twice, then obtain the lock, and reclaim from there to two different places, but crucially reclaim the same entry twice, resulting in the WARN_ONCE() a little later. Fix that by reading txq->read_ptr under lock. Signed-off-by: Johannes Berg Signed-off-by: Miri Korenblit Link: https://msgid.link/20240319100755.bf4c62196504.I978a7ca56c6bd6f1bf42c15aa923ba03366a840b@changeid Signed-off-by: Johannes Berg --- diff --git a/drivers/net/wireless/intel/iwlwifi/queue/tx.c b/drivers/net/wireless/intel/iwlwifi/queue/tx.c index 33973a60d0bf4..6229c785c8457 100644 --- a/drivers/net/wireless/intel/iwlwifi/queue/tx.c +++ b/drivers/net/wireless/intel/iwlwifi/queue/tx.c @@ -1589,9 +1589,9 @@ void iwl_txq_reclaim(struct iwl_trans *trans, int txq_id, int ssn, return; tfd_num = iwl_txq_get_cmd_index(txq, ssn); - read_ptr = iwl_txq_get_cmd_index(txq, txq->read_ptr); spin_lock_bh(&txq->lock); + read_ptr = iwl_txq_get_cmd_index(txq, txq->read_ptr); if (!test_bit(txq_id, trans->txqs.queue_used)) { IWL_DEBUG_TX_QUEUES(trans, "Q %d inactive - ignoring idx %d\n",