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authorStanislaw Gruszka <sgruszka@redhat.com>2011-04-20 15:57:14 +0200
committerGreg Kroah-Hartman <gregkh@suse.de>2011-05-09 15:06:37 -0700
commit0d15c412b9d90238f94d1ec0100f4035582b29cf (patch)
treeb63a84c937923d545a30a2dc459ec483ab09952c /drivers
parent5a19c7ecdc631407d490d206b80ed790daad99cd (diff)
downloadlinux-linaro-android-0d15c412b9d90238f94d1ec0100f4035582b29cf.tar.gz
iwlwifi: fix skb usage after free
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>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/net/wireless/iwlwifi/iwl-agn-tx.c10
1 files changed, 7 insertions, 3 deletions
diff --git a/drivers/net/wireless/iwlwifi/iwl-agn-tx.c b/drivers/net/wireless/iwlwifi/iwl-agn-tx.c
index 24a11b8f73b..f5aaf31c4c1 100644
--- a/drivers/net/wireless/iwlwifi/iwl-agn-tx.c
+++ b/drivers/net/wireless/iwlwifi/iwl-agn-tx.c
@@ -1207,12 +1207,16 @@ int iwlagn_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];
- iwlagn_tx_status(priv, tx_info,
- txq_id >= IWLAGN_FIRST_AMPDU_QUEUE);
+
+ if (WARN_ON_ONCE(tx_info->skb == NULL))
+ continue;
hdr = (struct ieee80211_hdr *)tx_info->skb->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,
+ txq_id >= IWLAGN_FIRST_AMPDU_QUEUE);
tx_info->skb = NULL;
if (priv->cfg->ops->lib->txq_inval_byte_cnt_tbl)