This is a note to let you know that I've just added the patch titled
xen-netback: fix a BUG() during initialization
to the 4.1-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
xen-netback-fix-a-bug-during-initialization.patch
and it can be found in the queue-4.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From foo@baz Fri Jul 3 20:00:25 PDT 2015
From: "Palik, Imre" <[email protected]>
Date: Fri, 19 Jun 2015 14:21:51 +0200
Subject: xen-netback: fix a BUG() during initialization
From: "Palik, Imre" <[email protected]>
[ Upstream commit 12b322ac85208de564ecf23aa754d796a91de21f ]
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 <[email protected]>
Cc: Matt Wilson <[email protected]>
Acked-by: Wei Liu <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
drivers/net/xen-netback/xenbus.c | 4 ++++
1 file changed, 4 insertions(+)
--- a/drivers/net/xen-netback/xenbus.c
+++ b/drivers/net/xen-netback/xenbus.c
@@ -681,6 +681,9 @@ static int xen_register_watchers(struct
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
}
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);
Patches currently in stable-queue which might be from [email protected] are
queue-4.1/xen-netback-fix-a-bug-during-initialization.patch
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