[Xen-devel] [PATCH 08/11] xen/hvm kexec: unregister the watch of the "backend" node during reboot

[Olaf Hering <olaf@xxxxxxxxx>]

The watch of the xenstore "backend" node has to be unregistered during a
kexec reboot. Otherwise the kexec kernel will crash due to a memory
corruption because more than one watch is registered on that node.

v2:
 use kexec_is_loaded() function

Signed-off-by: Olaf Hering <olaf@xxxxxxxxx>

---
 drivers/xen/xenbus/xenbus_probe_backend.c |   15 +++++++++++++++
 1 file changed, 15 insertions(+)

Index: linux-3.0/drivers/xen/xenbus/xenbus_probe_backend.c
===================================================================
--- linux-3.0.orig/drivers/xen/xenbus/xenbus_probe_backend.c
+++ linux-3.0/drivers/xen/xenbus/xenbus_probe_backend.c
@@ -42,6 +42,8 @@
 #include <linux/fcntl.h>
 #include <linux/mm.h>
 #include <linux/notifier.h>
+#include <linux/kexec.h>
+#include <linux/syscore_ops.h>
 
 #include <asm/page.h>
 #include <asm/pgtable.h>
@@ -255,6 +257,18 @@ static int backend_probe_and_watch(struc
        return NOTIFY_DONE;
 }
 
+static void xenbus_backend_shutdown_watcher(void)
+{
+       if (!kexec_is_loaded())
+               return;
+
+       unregister_xenbus_watch(&be_watch);
+}
+
+static struct syscore_ops xenbus_backend_watcher_syscore_ops = {
+       .shutdown = xenbus_backend_shutdown_watcher,
+};
+
 static int __init xenbus_probe_backend_init(void)
 {
        static struct notifier_block xenstore_notifier = {
@@ -270,6 +284,7 @@ static int __init xenbus_probe_backend_i
                return err;
 
        register_xenstore_notifier(&xenstore_notifier);
+       register_syscore_ops(&xenbus_backend_watcher_syscore_ops);
 
        return 0;
 }


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel