From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965204Ab2CMAYu (ORCPT ); Mon, 12 Mar 2012 20:24:50 -0400 Received: from mail.windriver.com ([147.11.1.11]:48810 "EHLO mail.windriver.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965137Ab2CMAYm (ORCPT ); Mon, 12 Mar 2012 20:24:42 -0400 From: Paul Gortmaker To: stable@kernel.org, linux-kernel@vger.kernel.org Cc: stable-review@kernel.org, Stanislaw Gruszka , "John W. Linville" , Paul Gortmaker Subject: [34-longterm 167/196] iwlwifi: fix skb usage after free Date: Mon, 12 Mar 2012 20:21:20 -0400 Message-Id: <1331598109-31424-122-git-send-email-paul.gortmaker@windriver.com> X-Mailer: git-send-email 1.7.9.3 In-Reply-To: <1331598109-31424-1-git-send-email-paul.gortmaker@windriver.com> References: <1331597724-31358-1-git-send-email-paul.gortmaker@windriver.com> <1331598109-31424-1-git-send-email-paul.gortmaker@windriver.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Stanislaw Gruszka ------------------- This is a commit scheduled for the next v2.6.34 longterm release. If you see a problem with using this for longterm, please comment. ------------------- commit b25026981aecde3685dd0e45ad980fff9f528daa upstream. Since commit a120e912eb51e347f36c71b60a1d13af74d30e83 Author: Stanislaw Gruszka 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. [PG: since 34, file renamed, + iwlagn_tx_status --> iwl_tx_status] Signed-off-by: Stanislaw Gruszka Acked-by: Wey-Yi Guy Signed-off-by: John W. Linville Signed-off-by: Paul Gortmaker --- drivers/net/wireless/iwlwifi/iwl-tx.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/drivers/net/wireless/iwlwifi/iwl-tx.c b/drivers/net/wireless/iwlwifi/iwl-tx.c index e950153..92a5f9e 100644 --- a/drivers/net/wireless/iwlwifi/iwl-tx.c +++ b/drivers/net/wireless/iwlwifi/iwl-tx.c @@ -1234,11 +1234,15 @@ int iwl_tx_queue_reclaim(struct iwl_priv *priv, int txq_id, int index) q->read_ptr = iwl_queue_inc_wrap(q->read_ptr, q->n_bd)) { tx_info = &txq->txb[txq->q.read_ptr]; - iwl_tx_status(priv, tx_info->skb[0]); + + if (WARN_ON_ONCE(tx_info->skb == 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++; + + iwl_tx_status(priv, tx_info->skb[0]); tx_info->skb[0] = NULL; if (priv->cfg->ops->lib->txq_inval_byte_cnt_tbl) -- 1.7.9.3