Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit cefde4e7 authored by Tianyu Lan's avatar Tianyu Lan Committed by Greg Kroah-Hartman
Browse files

x86/Hyper-V: Trigger crash enlightenment only once during system crash. 



[ Upstream commit 73f26e526f19afb3a06b76b970a76bcac2cafd05 ]

When a guest VM panics, Hyper-V should be notified only once via the
crash synthetic MSRs.  Current Linux code might write these crash MSRs
twice during a system panic:
1) hyperv_panic/die_event() calling hyperv_report_panic()
2) hv_kmsg_dump() calling hyperv_report_panic_msg()

Fix this by not calling hyperv_report_panic() if a kmsg dump has been
successfully registered.  The notification will happen later via
hyperv_report_panic_msg().

Fixes: 7ed4325a ("Drivers: hv: vmbus: Make panic reporting to be more useful")
Reviewed-by: default avatarMichael Kelley <mikelley@microsoft.com>
Signed-off-by: default avatarTianyu Lan <Tianyu.Lan@microsoft.com>
Link: https://lore.kernel.org/r/20200406155331.2105-4-Tianyu.Lan@microsoft.com


Signed-off-by: default avatarWei Liu <wei.liu@kernel.org>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent 89b0b47a

drivers/hv/vmbus_drv.c

+14 −2
Original line number Original line Diff line number Diff line
@@ -65,7 +65,13 @@ static int hyperv_panic_event(struct notifier_block *nb, unsigned long val, 




	vmbus_initiate_unload(true);

	vmbus_initiate_unload(true);





	if (ms_hyperv.misc_features & HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE) {

	/*

	 * 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

	 * the notification here.

	 */

	if (ms_hyperv.misc_features & HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE

	    && !hv_panic_page) {

		regs = current_pt_regs();

		regs = current_pt_regs();

		hyperv_report_panic(regs, val);

		hyperv_report_panic(regs, val);

	}

	}
@@ -78,6 +84,12 @@ static int hyperv_die_event(struct notifier_block *nb, unsigned long val, 
	struct die_args *die = (struct die_args *)args;

	struct die_args *die = (struct die_args *)args;

	struct pt_regs *regs = die->regs;

	struct pt_regs *regs = die->regs;





	/*

	 * 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

	 * the notification here.

	 */

	if (!hv_panic_page)

		hyperv_report_panic(regs, val);

		hyperv_report_panic(regs, val);

	return NOTIFY_DONE;

	return NOTIFY_DONE;

}

}