2.6.35-longterm review patch. If anyone has any objections, please let me know.
------------------ Date: Wed, 20 Apr 2011 15:57:14 +0200 Subject: iwlwifi: fix skb usage after free [AK: Did some changes for the backport to .35. Stanislaw, please verify them] Since commit a120e912eb51e347f36c71b60a1d13af74d30e83 Author: Stanislaw Gruszka <[email protected]> Date: Fri Feb 19 15:47:33 2010 -0800 iwlwifi: sanity check before counting number of tfds can be free we use skb->data after calling ieee80211_tx_status_irqsafe(), which could free skb instantly. On current kernels I do not observe practical problems related with bug, but on 2.6.35.y it cause random system hangs when stressing wireless link. Cc: [email protected] # 2.6.32+ Signed-off-by: Stanislaw Gruszka <[email protected]> Signed-off-by: Andi Kleen <[email protected]> --- drivers/net/wireless/iwlwifi/iwl-agn-tx.c | 10 +++++++--- 1 files changed, 7 insertions(+), 3 deletions(-) Index: linux-2.6.35.y/drivers/net/wireless/iwlwifi/iwl-agn-tx.c =================================================================== --- linux-2.6.35.y.orig/drivers/net/wireless/iwlwifi/iwl-agn-tx.c +++ linux-2.6.35.y/drivers/net/wireless/iwlwifi/iwl-agn-tx.c @@ -1141,11 +1141,14 @@ int iwlagn_tx_queue_reclaim(struct iwl_p q->read_ptr = iwl_queue_inc_wrap(q->read_ptr, q->n_bd)) { tx_info = &txq->txb[txq->q.read_ptr]; - iwlagn_tx_status(priv, tx_info->skb[0]); + + if (WARN_ON_ONCE(tx_info->skb[0] == NULL)) + continue; hdr = (struct ieee80211_hdr *)tx_info->skb[0]->data; - if (hdr && ieee80211_is_data_qos(hdr->frame_control)) + if (ieee80211_is_data_qos(hdr->frame_control)) nfreed++; + iwlagn_tx_status(priv, tx_info->skb[0]); tx_info->skb[0] = NULL; if (priv->cfg->ops->lib->txq_inval_byte_cnt_tbl) _______________________________________________ stable mailing list [email protected] http://linux.kernel.org/mailman/listinfo/stable
