Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [ 43/53] xen-netback: correctly return errors from netbk_count_requests() | Date | Tue, 26 Feb 2013 15:58:12 -0800 |
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3.0-stable review patch. If anyone has any objections, please let me know.
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From: David Vrabel <david.vrabel@citrix.com>
[ 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 <wei.liu2@citrix.com> Signed-off-by: Jan Beulich <JBeulich@suse.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com> Reported-by: Christopher S. Aker <caker@theshore.net> Acked-by: Ian Campbell <ian.campbell@citrix.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- drivers/net/xen-netback/netback.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)
--- a/drivers/net/xen-netback/netback.c +++ b/drivers/net/xen-netback/netback.c @@ -870,13 +870,13 @@ static int netbk_count_requests(struct x 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), @@ -884,7 +884,7 @@ static int netbk_count_requests(struct x 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; @@ -894,7 +894,7 @@ static int netbk_count_requests(struct x 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;
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