David Vrabel
2013-Feb-14 13:18 UTC
[PATCH 1/2] xen-netback: correctly return errors from netbk_count_requests()
From: David Vrabel <david.vrabel@citrix.com>
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>
---
drivers/net/xen-netback/netback.c | 8 ++++----
1 files 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;
--
1.7.2.5
Ian Campbell
2013-Feb-14 16:39 UTC
Re: [PATCH 1/2] xen-netback: correctly return errors from netbk_count_requests()
On Thu, 2013-02-14 at 13:18 +0000, David Vrabel wrote:> From: David Vrabel <david.vrabel@citrix.com> > > 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> Although I would like to add a Tested-by: Christopher too if possible. David (M) this should go to stable please.> --- > drivers/net/xen-netback/netback.c | 8 ++++---- > 1 files 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;