This is a note to let you know that I've just added the patch titled
x86/Hyper-V: Report crash register data or kmsg before running crash kernel
to the 5.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
x86-hyper-v-report-crash-register-data-or-kmsg-before-running-crash-kernel.patch
and it can be found in the queue-5.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From a11589563e96bf262767294b89b25a9d44e7303b Mon Sep 17 00:00:00 2001
From: Tianyu Lan <Tianyu.Lan@xxxxxxxxxxxxx>
Date: Mon, 6 Apr 2020 08:53:29 -0700
Subject: x86/Hyper-V: Report crash register data or kmsg before running crash kernel
From: Tianyu Lan <Tianyu.Lan@xxxxxxxxxxxxx>
commit a11589563e96bf262767294b89b25a9d44e7303b upstream.
We want to notify Hyper-V when a Linux guest VM crash occurs, so
there is a record of the crash even when kdump is enabled. But
crash_kexec_post_notifiers defaults to "false", so the kdump kernel
runs before the notifiers and Hyper-V never gets notified. Fix this by
always setting crash_kexec_post_notifiers to be true for Hyper-V VMs.
Fixes: 81b18bce48af ("Drivers: HV: Send one page worth of kmsg dump over Hyper-V during panic")
Reviewed-by: Michael Kelley <mikelley@xxxxxxxxxxxxx>
Signed-off-by: Tianyu Lan <Tianyu.Lan@xxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20200406155331.2105-5-Tianyu.Lan@xxxxxxxxxxxxx
Signed-off-by: Wei Liu <wei.liu@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/kernel/cpu/mshyperv.c | 10 ++++++++++
1 file changed, 10 insertions(+)
--- a/arch/x86/kernel/cpu/mshyperv.c
+++ b/arch/x86/kernel/cpu/mshyperv.c
@@ -263,6 +263,16 @@ static void __init ms_hyperv_init_platfo
cpuid_eax(HYPERV_CPUID_NESTED_FEATURES);
}
+ /*
+ * Hyper-V expects to get crash register data or kmsg when
+ * crash enlightment is available and system crashes. Set
+ * crash_kexec_post_notifiers to be true to make sure that
+ * calling crash enlightment interface before running kdump
+ * kernel.
+ */
+ if (ms_hyperv.misc_features & HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE)
+ crash_kexec_post_notifiers = true;
+
#ifdef CONFIG_X86_LOCAL_APIC
if (ms_hyperv.features & HV_X64_ACCESS_FREQUENCY_MSRS &&
ms_hyperv.misc_features & HV_FEATURE_FREQUENCY_MSRS_AVAILABLE) {
Patches currently in stable-queue which might be from Tianyu.Lan@xxxxxxxxxxxxx are
queue-5.4/x86-hyper-v-unload-vmbus-channel-in-hv-panic-callback.patch
queue-5.4/x86-hyper-v-trigger-crash-enlightenment-only-once-during-system-crash.patch
queue-5.4/x86-hyper-v-report-crash-register-data-or-kmsg-before-running-crash-kernel.patch
queue-5.4/x86-hyper-v-report-crash-register-data-when-sysctl_record_panic_msg-is-not-set.patch
queue-5.4/x86-hyper-v-report-crash-data-in-die-when-panic_on_oops-is-set.patch
