On 2017年10月25日 15:23, Girish Moodalbail wrote:
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.moodalb...@oracle.com> --- v1 -> v2: - took care of an another issue in failure path of skb_array_init --- drivers/net/tap.c | 18 +++++++++--------- 1 file changed, 9 insertions(+), 9 deletions(-) diff --git a/drivers/net/tap.c b/drivers/net/tap.c index 21b71ae..98ee6cc 100644 --- a/drivers/net/tap.c +++ b/drivers/net/tap.c @@ -517,6 +517,10 @@ static int tap_open(struct inode *inode, struct file *file) &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, struct file *file) 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)
Acked-by: Jason Wang <jasow...@redhat.com> This patch is needed for -stable. Thanks
