From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932613Ab1EFAg6 (ORCPT ); Thu, 5 May 2011 20:36:58 -0400 Received: from kroah.org ([198.145.64.141]:37417 "EHLO coco.kroah.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932530Ab1EFA0M (ORCPT ); Thu, 5 May 2011 20:26:12 -0400 X-Mailbox-Line: From gregkh@clark.kroah.org Thu May 5 17:22:19 2011 Message-Id: <20110506002219.018445926@clark.kroah.org> User-Agent: quilt/0.48-16.4 Date: Thu, 05 May 2011 17:22:05 -0700 From: Greg KH To: linux-kernel@vger.kernel.org, stable@kernel.org Cc: stable-review@kernel.org, torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Stanislaw Gruszka , Wey-Yi Guy , "John W. Linville" Subject: [140/143] iwlwifi: fix skb usage after free In-Reply-To: <20110506002311.GA15354@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 2.6.32-longterm review patch. If anyone has any objections, please let us know. ------------------ From: Stanislaw Gruszka 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. Signed-off-by: Stanislaw Gruszka Acked-by: Wey-Yi Guy Signed-off-by: John W. Linville Signed-off-by: Greg Kroah-Hartman --- drivers/net/wireless/iwlwifi/iwl-tx.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) --- a/drivers/net/wireless/iwlwifi/iwl-tx.c +++ b/drivers/net/wireless/iwlwifi/iwl-tx.c @@ -1088,11 +1088,15 @@ int iwl_tx_queue_reclaim(struct iwl_priv q->read_ptr = iwl_queue_inc_wrap(q->read_ptr, q->n_bd)) { tx_info = &txq->txb[txq->q.read_ptr]; - ieee80211_tx_status_irqsafe(priv->hw, 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++; + + ieee80211_tx_status_irqsafe(priv->hw, tx_info->skb[0]); tx_info->skb[0] = NULL; if (priv->cfg->ops->lib->txq_inval_byte_cnt_tbl)