From: ltykernel@gmail.com
To: kys@microsoft.com, haiyangz@microsoft.com,
sthemmin@microsoft.com, liuwe@microsoft.com, tglx@linutronix.de,
mingo@redhat.com, bp@alien8.de, hpa@zytor.com, x86@kernel.org,
michael.h.kelley@microsoft.com
Cc: Tianyu Lan <Tianyu.Lan@microsoft.com>,
linux-hyperv@vger.kernel.org, linux-kernel@vger.kernel.org,
vkuznets@redhat.com
Subject: [PATCH V3 3/6] x86/Hyper-V: Trigger crash enlightenment only once during system crash.
Date: Tue, 24 Mar 2020 00:57:17 -0700 [thread overview]
Message-ID: <20200324075720.9462-4-Tianyu.Lan@microsoft.com> (raw)
In-Reply-To: <20200324075720.9462-1-Tianyu.Lan@microsoft.com>
From: Tianyu Lan <Tianyu.Lan@microsoft.com>
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().
Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com>
---
Change since v1:
- Update commit log
Change since v2:
- Update comment
---
drivers/hv/vmbus_drv.c | 16 ++++++++++++++--
1 file changed, 14 insertions(+), 2 deletions(-)
diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index 00a511f15926..333dad39b1c1 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -55,7 +55,13 @@ static int hyperv_panic_event(struct notifier_block *nb, unsigned long val,
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();
hyperv_report_panic(regs, val);
}
@@ -68,7 +74,13 @@ 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;
- hyperv_report_panic(regs, val);
+ /*
+ * 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);
return NOTIFY_DONE;
}
--
2.14.5
next prev parent reply other threads:[~2020-03-24 7:57 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-24 7:57 [PATCH V3 0/6] x86/Hyper-V: Panic code path fixes ltykernel
2020-03-24 7:57 ` [PATCH V3 1/6] x86/Hyper-V: Unload vmbus channel in hv panic callback ltykernel
2020-03-25 18:28 ` Michael Kelley
2020-03-24 7:57 ` [PATCH V3 2/6] x86/Hyper-V: Free hv_panic_page when fail to register kmsg dump ltykernel
2020-03-25 18:30 ` Michael Kelley
2020-03-24 7:57 ` ltykernel [this message]
2020-03-25 18:31 ` [PATCH V3 3/6] x86/Hyper-V: Trigger crash enlightenment only once during system crash Michael Kelley
2020-03-24 7:57 ` [PATCH V3 4/6] x86/Hyper-V: Report crash register data or ksmg before running crash kernel ltykernel
2020-03-25 18:33 ` Michael Kelley
2020-03-24 7:57 ` [PATCH V3 5/6] x86/Hyper-V: Report crash register data when sysctl_record_panic_msg is not set ltykernel
2020-03-25 18:34 ` Michael Kelley
2020-03-24 7:57 ` [PATCH V3 6/6] x86/Hyper-V: Report crash data in die() when panic_on_oops is set ltykernel
2020-03-25 18:36 ` Michael Kelley
2020-03-31 7:38 ` [PATCH V4 " ltykernel
2020-03-31 13:51 ` Michael Kelley
2020-03-31 14:26 ` Tianyu Lan
2020-04-01 18:53 ` Wei Liu
2020-04-02 12:51 ` Tianyu Lan
2020-03-30 10:13 ` [PATCH V3 0/6] x86/Hyper-V: Panic code path fixes Wei Liu
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