[PATCH 127/139] xen-netback: correctly return errors from netbk_count_requests()
Luis Henriques
luis.henriques at canonical.com
Thu Feb 28 14:44:37 UTC 2013
3.5.7.7 -stable review patch. If anyone has any objections, please let me know.
------------------
From: David Vrabel <david.vrabel at citrix.com>
commit 35876b5ffc154c357476b2c3bdab10feaf4bd8f0 upstream.
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 at citrix.com>
Signed-off-by: Jan Beulich <JBeulich at suse.com>
Signed-off-by: David Vrabel <david.vrabel at citrix.com>
Reported-by: Christopher S. Aker <caker at theshore.net>
Acked-by: Ian Campbell <ian.campbell at citrix.com>
Signed-off-by: David S. Miller <davem at davemloft.net>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
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 f3c3a68..a98f012 100644
--- a/drivers/net/xen-netback/netback.c
+++ b/drivers/net/xen-netback/netback.c
@@ -882,13 +882,13 @@ 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),
@@ -896,7 +896,7 @@ 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;
@@ -906,7 +906,7 @@ 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;
--
1.8.1.2
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