From 8f56788f8d42ce5b5888ab7e9e7270646bcacd48 Mon Sep 17 00:00:00 2001 From: David Vrabel Date: Thu, 14 Feb 2013 03:18:57 +0000 Subject: [PATCH] xen-netback: correctly return errors from netbk_count_requests() [ Upstream commit 35876b5ffc154c357476b2c3bdab10feaf4bd8f0 ] netbk_count_requests() could detect an error, call netbk_fatal_tx_error() but return 0. The vif may then be used afterwards (e.g., in a call to netbk_tx_error(). Since netbk_fatal_tx_error() could set vif->refcnt to 1, the vif may be freed immediately after the call to netbk_fatal_tx_error() (e.g., if the vif is also removed). Netback thread Xenwatch thread ------------------------------------------- netbk_fatal_tx_err() netback_remove() xenvif_disconnect() ... free_netdev() netbk_tx_err() Oops! Signed-off-by: Wei Liu Signed-off-by: Jan Beulich Signed-off-by: David Vrabel Reported-by: Christopher S. Aker Acked-by: Ian Campbell Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- drivers/net/xen-netback/netback.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c index 2b9520c..cd49ba9 100644 --- a/drivers/net/xen-netback/netback.c +++ b/drivers/net/xen-netback/netback.c @@ -911,13 +911,13 @@ static int netbk_count_requests(struct xenvif *vif, if (frags >= work_to_do) { netdev_err(vif->dev, "Need more frags\n"); netbk_fatal_tx_err(vif); - return -frags; + return -ENODATA; } if (unlikely(frags >= MAX_SKB_FRAGS)) { netdev_err(vif->dev, "Too many frags\n"); netbk_fatal_tx_err(vif); - return -frags; + return -E2BIG; } memcpy(txp, RING_GET_REQUEST(&vif->tx, cons + frags), @@ -925,7 +925,7 @@ static int netbk_count_requests(struct xenvif *vif, if (txp->size > first->size) { netdev_err(vif->dev, "Frag is bigger than frame.\n"); netbk_fatal_tx_err(vif); - return -frags; + return -EIO; } first->size -= txp->size; @@ -935,7 +935,7 @@ static int netbk_count_requests(struct xenvif *vif, netdev_err(vif->dev, "txp->offset: %x, size: %u\n", txp->offset, txp->size); netbk_fatal_tx_err(vif); - return -frags; + return -EINVAL; } } while ((txp++)->flags & XEN_NETTXF_more_data); return frags; -- 2.7.4