| From b25026981aecde3685dd0e45ad980fff9f528daa Mon Sep 17 00:00:00 2001 |
| From: Stanislaw Gruszka <sgruszka@redhat.com> |
| Date: Wed, 20 Apr 2011 15:57:14 +0200 |
| Subject: iwlwifi: fix skb usage after free |
| |
| From: Stanislaw Gruszka <sgruszka@redhat.com> |
| |
| commit b25026981aecde3685dd0e45ad980fff9f528daa upstream. |
| |
| Since |
| |
| commit a120e912eb51e347f36c71b60a1d13af74d30e83 |
| Author: Stanislaw Gruszka <sgruszka@redhat.com> |
| 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 <sgruszka@redhat.com> |
| Acked-by: Wey-Yi Guy <wey-yi.w.guy@intel.com> |
| Signed-off-by: John W. Linville <linville@tuxdriver.com> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> |
| |
| --- |
| 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 |
| @@ -1162,11 +1162,15 @@ 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]; |
| - 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) |
