4.13-stable review patch. If anyone has any objections, please let me know.
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From: Girish Moodalbail girish.moodalbail@oracle.com
[ Upstream commit 78e0ea6791d7baafb8a0ca82b1bd0c7b3453c919 ]
Double free of skb_array in tap module is causing kernel panic. When tap_set_queue() fails we free skb_array right away by calling skb_array_cleanup(). However, later on skb_array_cleanup() is called again by tap_sock_destruct through sock_put(). This patch fixes that issue.
Fixes: 362899b8725b35e3 (macvtap: switch to use skb array) Signed-off-by: Girish Moodalbail girish.moodalbail@oracle.com Acked-by: Jason Wang jasowang@redhat.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/net/tap.c | 18 +++++++++--------- 1 file changed, 9 insertions(+), 9 deletions(-)
--- a/drivers/net/tap.c +++ b/drivers/net/tap.c @@ -517,6 +517,10 @@ static int tap_open(struct inode *inode, &tap_proto, 0); if (!q) goto err; + if (skb_array_init(&q->skb_array, tap->dev->tx_queue_len, GFP_KERNEL)) { + sk_free(&q->sk); + goto err; + }
RCU_INIT_POINTER(q->sock.wq, &q->wq); init_waitqueue_head(&q->wq.wait); @@ -540,22 +544,18 @@ static int tap_open(struct inode *inode, if ((tap->dev->features & NETIF_F_HIGHDMA) && (tap->dev->features & NETIF_F_SG)) sock_set_flag(&q->sk, SOCK_ZEROCOPY);
- err = -ENOMEM; - if (skb_array_init(&q->skb_array, tap->dev->tx_queue_len, GFP_KERNEL)) - goto err_array; - err = tap_set_queue(tap, file, q); - if (err) - goto err_queue; + if (err) { + /* tap_sock_destruct() will take care of freeing skb_array */ + goto err_put; + }
dev_put(tap->dev);
rtnl_unlock(); return err;
-err_queue: - skb_array_cleanup(&q->skb_array); -err_array: +err_put: sock_put(&q->sk); err: if (tap)