Messages in this thread Patch in this message | | | Date | Thu, 05 May 2011 17:22:05 -0700 | From | Greg KH <> | Subject | [140/143] iwlwifi: fix skb usage after free |
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2.6.32-longterm review patch. If anyone has any objections, please let us know.
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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 @@ -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)
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