iwlwifi: fix skb usage after free
Since
commit a120e912eb
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.
Cc: stable@kernel.org # 2.6.32+
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>
This commit is contained in:
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@ -1224,12 +1224,16 @@ int iwlagn_tx_queue_reclaim(struct iwl_priv *priv, int txq_id, int index)
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q->read_ptr = iwl_queue_inc_wrap(q->read_ptr, q->n_bd)) {
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q->read_ptr = iwl_queue_inc_wrap(q->read_ptr, q->n_bd)) {
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tx_info = &txq->txb[txq->q.read_ptr];
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tx_info = &txq->txb[txq->q.read_ptr];
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iwlagn_tx_status(priv, tx_info,
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txq_id >= IWLAGN_FIRST_AMPDU_QUEUE);
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if (WARN_ON_ONCE(tx_info->skb == NULL))
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continue;
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hdr = (struct ieee80211_hdr *)tx_info->skb->data;
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hdr = (struct ieee80211_hdr *)tx_info->skb->data;
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if (hdr && ieee80211_is_data_qos(hdr->frame_control))
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if (ieee80211_is_data_qos(hdr->frame_control))
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nfreed++;
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nfreed++;
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iwlagn_tx_status(priv, tx_info,
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txq_id >= IWLAGN_FIRST_AMPDU_QUEUE);
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tx_info->skb = NULL;
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tx_info->skb = NULL;
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if (priv->cfg->ops->lib->txq_inval_byte_cnt_tbl)
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if (priv->cfg->ops->lib->txq_inval_byte_cnt_tbl)
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