6.1-stable review patch. If anyone has any objections, please let me know.
------------------
From: Yuho Choi <redacted>
[ Upstream commit d330fb86a7170f845123ae82d95df440fad9b707 ]
xs_init() registers xs_reboot_nb before initializing XenStore
communications and starting xenwatch. If either operation fails, the
notifier remains registered and a later initialization attempt can hit a
duplicate registration.
Check the notifier registration result and unregister it on every
subsequent failure path.
Fixes: fd8aa9095a95 ("xen: optimize xenbus driver for multiple concurrent xenstore accesses")
Signed-off-by: Yuho Choi <redacted>
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Message-ID: [off-list ref]
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/xen/xenbus/xenbus_xs.c | 16 ++++++++++++----
1 file changed, 12 insertions(+), 4 deletions(-)
diff --git a/drivers/xen/xenbus/xenbus_xs.c b/drivers/xen/xenbus/xenbus_xs.c
index a4dd92719e7ae..d59bc4f5169af 100644
--- a/drivers/xen/xenbus/xenbus_xs.c
+++ b/drivers/xen/xenbus/xenbus_xs.c
@@ -952,19 +952,27 @@ int xs_init(void)
int err;
struct task_struct *task;
- register_reboot_notifier(&xs_reboot_nb);
+ err = register_reboot_notifier(&xs_reboot_nb);
+ if (err)
+ return err;
/* Initialize the shared memory rings to talk to xenstored */
err = xb_init_comms();
if (err)
- return err;
+ goto err_unregister_reboot_notifier;
task = kthread_run(xenwatch_thread, NULL, "xenwatch");
- if (IS_ERR(task))
- return PTR_ERR(task);
+ if (IS_ERR(task)) {
+ err = PTR_ERR(task);
+ goto err_unregister_reboot_notifier;
+ }
/* shutdown watches for kexec boot */
xs_reset_watches();
return 0;
+
+err_unregister_reboot_notifier:
+ unregister_reboot_notifier(&xs_reboot_nb);
+ return err;
}--
2.53.0