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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 15:55:41 -0700
commit51028920a9424e2437d6acc3bbc0946d6d71a7aa (patch)
treefdf94fe0b9b3d001ed3dbda34022ef43495d0bba
parent49abf47d18ef1e3c67f3a29cd9eda03f48818652 (diff)
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>
-rw-r--r--drivers/net/wireless/iwlwifi/iwl-tx.c8
1 files changed, 6 insertions, 2 deletions
diff --git a/drivers/net/wireless/iwlwifi/iwl-tx.c b/drivers/net/wireless/iwlwifi/iwl-tx.c
index d21c06ea0ec3..c3d7dd669029 100644
--- 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 *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];
- 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)