This is a note to let you know that I've just added the patch titled mwifiex: Fix NULL pointer dereference in skb_dequeue() to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: mwifiex-fix-null-pointer-dereference-in-skb_dequeue.patch and it can be found in the queue-4.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From c44c040300d7afd79294710313a4989683e2afb1 Mon Sep 17 00:00:00 2001 From: Amitkumar Karwar <akarwar@xxxxxxxxxxx> Date: Wed, 28 Sep 2016 18:18:23 +0530 Subject: mwifiex: Fix NULL pointer dereference in skb_dequeue() From: Amitkumar Karwar <akarwar@xxxxxxxxxxx> commit c44c040300d7afd79294710313a4989683e2afb1 upstream. At couple of places in cleanup path, we are just going through the skb queue and freeing them without unlinking. This leads to a crash when other thread tries to do skb_dequeue() and use already freed node. The problem is freed by unlinking skb before freeing it. Signed-off-by: Amitkumar Karwar <akarwar@xxxxxxxxxxx> Signed-off-by: Kalle Valo <kvalo@xxxxxxxxxxxxxx> [AmitP: Refactored to fix driver file path in linux-4.4.y] Signed-off-by: Amit Pundir <amit.pundir@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/net/wireless/mwifiex/cfg80211.c | 4 +++- drivers/net/wireless/mwifiex/wmm.c | 12 +++++++++--- 2 files changed, 12 insertions(+), 4 deletions(-) --- a/drivers/net/wireless/mwifiex/cfg80211.c +++ b/drivers/net/wireless/mwifiex/cfg80211.c @@ -2839,8 +2839,10 @@ int mwifiex_del_virtual_intf(struct wiph mwifiex_stop_net_dev_queue(priv->netdev, adapter); - skb_queue_walk_safe(&priv->bypass_txq, skb, tmp) + skb_queue_walk_safe(&priv->bypass_txq, skb, tmp) { + skb_unlink(skb, &priv->bypass_txq); mwifiex_write_data_complete(priv->adapter, skb, 0, -1); + } if (netif_carrier_ok(priv->netdev)) netif_carrier_off(priv->netdev); --- a/drivers/net/wireless/mwifiex/wmm.c +++ b/drivers/net/wireless/mwifiex/wmm.c @@ -501,8 +501,10 @@ mwifiex_wmm_del_pkts_in_ralist_node(stru struct mwifiex_adapter *adapter = priv->adapter; struct sk_buff *skb, *tmp; - skb_queue_walk_safe(&ra_list->skb_head, skb, tmp) + skb_queue_walk_safe(&ra_list->skb_head, skb, tmp) { + skb_unlink(skb, &ra_list->skb_head); mwifiex_write_data_complete(adapter, skb, 0, -1); + } } /* @@ -598,11 +600,15 @@ mwifiex_clean_txrx(struct mwifiex_privat priv->adapter->if_ops.clean_pcie_ring(priv->adapter); spin_unlock_irqrestore(&priv->wmm.ra_list_spinlock, flags); - skb_queue_walk_safe(&priv->tdls_txq, skb, tmp) + skb_queue_walk_safe(&priv->tdls_txq, skb, tmp) { + skb_unlink(skb, &priv->tdls_txq); mwifiex_write_data_complete(priv->adapter, skb, 0, -1); + } - skb_queue_walk_safe(&priv->bypass_txq, skb, tmp) + skb_queue_walk_safe(&priv->bypass_txq, skb, tmp) { + skb_unlink(skb, &priv->bypass_txq); mwifiex_write_data_complete(priv->adapter, skb, 0, -1); + } atomic_set(&priv->adapter->bypass_tx_pending, 0); idr_for_each(&priv->ack_status_frames, mwifiex_free_ack_frame, NULL); Patches currently in stable-queue which might be from akarwar@xxxxxxxxxxx are queue-4.4/mwifiex-fix-p2p-device-doesn-t-find-in-scan-problem.patch queue-4.4/mwifiex-fix-null-pointer-dereference-in-skb_dequeue.patch