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authorPalik, Imre <imrep@amazon.de>2015-06-19 15:21:51 +0300
committerDavid S. Miller <davem@davemloft.net>2015-06-23 13:34:02 +0300
commit12b322ac85208de564ecf23aa754d796a91de21f (patch)
tree27923ea28478e5becfc6a226beddee2b9b71cc31 /drivers/net/xen-netback/xenbus.c
parent754bc547f0a79f7568b5b81c7fc0a8d044a6571a (diff)
downloadlinux-12b322ac85208de564ecf23aa754d796a91de21f.tar.xz
xen-netback: fix a BUG() during initialization
Commit edafc132baac ("xen-netback: making the bandwidth limiter runtime settable") introduced the capability to change the bandwidth rate limit at runtime. But it also introduced a possible crashing bug. If netback receives two XenbusStateConnected without getting the hotplug-status watch firing in between, then it will try to register the watches for the rate limiter again. But this triggers a BUG() in the watch registration code. The fix modifies connect() to remove the possibly existing packet-rate watches before trying to install those watches. This behaviour is in line with how connect() deals with the hotplug-status watch. Signed-off-by: Imre Palik <imrep@amazon.de> Cc: Matt Wilson <msw@amazon.com> Acked-by: Wei Liu <wei.liu2@citrix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net/xen-netback/xenbus.c')
-rw-r--r--drivers/net/xen-netback/xenbus.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/drivers/net/xen-netback/xenbus.c b/drivers/net/xen-netback/xenbus.c
index 968787abf78d..ec383b0f5443 100644
--- a/drivers/net/xen-netback/xenbus.c
+++ b/drivers/net/xen-netback/xenbus.c
@@ -681,6 +681,9 @@ static int xen_register_watchers(struct xenbus_device *dev, struct xenvif *vif)
char *node;
unsigned maxlen = strlen(dev->nodename) + sizeof("/rate");
+ if (vif->credit_watch.node)
+ return -EADDRINUSE;
+
node = kmalloc(maxlen, GFP_KERNEL);
if (!node)
return -ENOMEM;
@@ -770,6 +773,7 @@ static void connect(struct backend_info *be)
}
xen_net_read_rate(dev, &credit_bytes, &credit_usec);
+ xen_unregister_watchers(be->vif);
xen_register_watchers(dev, be->vif);
read_xenbus_vif_flags(be);