[SRU][FOCAL/linux-azure][BIONIC/linux-azure-4.15][PATCH 1/1] Drivers: hv: vmbus: Only notify Hyper-V for die events that are oops

[William Breathitt Gray]

From: Michael Kelley <mikelley at microsoft.com>

Hyper-V currently may be notified of a panic for any die event. But
this results in false panic notifications for various user space traps
that are die events. Fix this by ignoring die events that aren't oops.

Fixes: 510f7aef65bb ("Drivers: hv: vmbus: prefer 'die' notification chain to 'panic'")
Signed-off-by: Michael Kelley <mikelley at microsoft.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets at redhat.com>
Link: https://lore.kernel.org/r/1596730935-11564-1-git-send-email-mikelley@microsoft.com
Signed-off-by: Wei Liu <wei.liu at kernel.org>

BugLink: https://bugs.launchpad.net/bugs/1891222

(cherry picked from commit 608a973bd52ef1705941b18f55e39655fcfe9cdb)
Signed-off-by: William Breathitt Gray <william.gray at canonical.com>
---
 drivers/hv/vmbus_drv.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index 0f168f0b1a8f..c97f1964d9ed 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -97,6 +97,10 @@ static int hyperv_die_event(struct notifier_block *nb, unsigned long val,
 	struct die_args *die = (struct die_args *)args;
 	struct pt_regs *regs = die->regs;
 
+	/* Don't notify Hyper-V if the die event is other than oops */
+	if (val != DIE_OOPS)
+		return NOTIFY_DONE;
+
 	/*
 	 * Hyper-V should be notified only once about a panic.  If we will be
 	 * doing hyperv_report_panic_msg() later with kmsg data, don't do
-- 
2.25.1