This is a note to let you know that I've just added the patch titled Drivers: hv: vmbus: Deactivate sysctl_record_panic_msg by default in isolated guests to the 5.17-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: drivers-hv-vmbus-deactivate-sysctl_record_panic_msg-.patch and it can be found in the queue-5.17 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit bfac634ec7d938c665a285476d58ecb01ceb5859 Author: Andrea Parri (Microsoft) <parri.andrea@xxxxxxxxx> Date: Tue Mar 1 15:11:35 2022 +0100 Drivers: hv: vmbus: Deactivate sysctl_record_panic_msg by default in isolated guests [ Upstream commit 9f8b577f7b43b2170628d6c537252785dcc2dcea ] hv_panic_page might contain guest-sensitive information, do not dump it over to Hyper-V by default in isolated guests. While at it, update some comments in hyperv_{panic,die}_event(). Reported-by: Dexuan Cui <decui@xxxxxxxxxxxxx> Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@xxxxxxxxx> Reviewed-by: Dexuan Cui <decui@xxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20220301141135.2232-1-parri.andrea@xxxxxxxxx Signed-off-by: Wei Liu <wei.liu@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c index 4bea1dfa41cd..6c057c76c2ca 100644 --- a/drivers/hv/vmbus_drv.c +++ b/drivers/hv/vmbus_drv.c @@ -77,8 +77,8 @@ static int hyperv_panic_event(struct notifier_block *nb, unsigned long 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. + * doing hv_kmsg_dump() with kmsg data later, don't do the notification + * here. */ if (ms_hyperv.misc_features & HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE && hyperv_report_reg()) { @@ -100,8 +100,8 @@ static int hyperv_die_event(struct notifier_block *nb, unsigned long 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. + * doing hv_kmsg_dump() with kmsg data later, don't do the notification + * here. */ if (hyperv_report_reg()) hyperv_report_panic(regs, val, true); @@ -1546,14 +1546,20 @@ static int vmbus_bus_init(void) if (ret) goto err_connect; + if (hv_is_isolation_supported()) + sysctl_record_panic_msg = 0; + /* * Only register if the crash MSRs are available */ if (ms_hyperv.misc_features & HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE) { u64 hyperv_crash_ctl; /* - * Sysctl registration is not fatal, since by default - * reporting is enabled. + * Panic message recording (sysctl_record_panic_msg) + * is enabled by default in non-isolated guests and + * disabled by default in isolated guests; the panic + * message recording won't be available in isolated + * guests should the following registration fail. */ hv_ctl_table_hdr = register_sysctl_table(hv_root_table); if (!hv_ctl_table_hdr)