lkml.org 
[lkml]   [2011]   [May]   [5]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    Date
    From
    Subject[140/143] iwlwifi: fix skb usage after free
    2.6.32-longterm review patch.  If anyone has any objections, please let us know.

    ------------------

    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)



    \
     
     \ /
      Last update: 2011-05-06 02:39    [W:4.186 / U:0.104 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site