From b4370df2b1f5158de028e167974263c5757b34a6 Mon Sep 17 00:00:00 2001 From: Vitaly Kuznetsov Date: Sat, 1 Aug 2015 16:08:09 -0700 Subject: Drivers: hv: vmbus: add special crash handler Full kernel hang is observed when kdump kernel starts after a crash. This hang happens in vmbus_negotiate_version() function on wait_for_completion() as Hyper-V host (Win2012R2 in my testing) never responds to CHANNELMSG_INITIATE_CONTACT as it thinks the connection is already established. We need to perform some mandatory minimalistic cleanup before we start new kernel. Reported-by: K. Y. Srinivasan Signed-off-by: Vitaly Kuznetsov Signed-off-by: K. Y. Srinivasan Signed-off-by: Greg Kroah-Hartman --- arch/x86/kernel/cpu/mshyperv.c | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) (limited to 'arch/x86/kernel/cpu/mshyperv.c') diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c index fa483ed4756e..5ea5bbcc85b3 100644 --- a/arch/x86/kernel/cpu/mshyperv.c +++ b/arch/x86/kernel/cpu/mshyperv.c @@ -35,6 +35,7 @@ struct ms_hyperv_info ms_hyperv; EXPORT_SYMBOL_GPL(ms_hyperv); static void (*hv_kexec_handler)(void); +static void (*hv_crash_handler)(struct pt_regs *regs); #if IS_ENABLED(CONFIG_HYPERV) static void (*vmbus_handler)(void); @@ -83,6 +84,18 @@ void hv_remove_kexec_handler(void) hv_kexec_handler = NULL; } EXPORT_SYMBOL_GPL(hv_remove_kexec_handler); + +void hv_setup_crash_handler(void (*handler)(struct pt_regs *regs)) +{ + hv_crash_handler = handler; +} +EXPORT_SYMBOL_GPL(hv_setup_crash_handler); + +void hv_remove_crash_handler(void) +{ + hv_crash_handler = NULL; +} +EXPORT_SYMBOL_GPL(hv_remove_crash_handler); #endif static void hv_machine_shutdown(void) @@ -92,6 +105,14 @@ static void hv_machine_shutdown(void) native_machine_shutdown(); } +static void hv_machine_crash_shutdown(struct pt_regs *regs) +{ + if (hv_crash_handler) + hv_crash_handler(regs); + native_machine_crash_shutdown(regs); +} + + static uint32_t __init ms_hyperv_platform(void) { u32 eax; @@ -165,6 +186,7 @@ static void __init ms_hyperv_init_platform(void) #endif machine_ops.shutdown = hv_machine_shutdown; + machine_ops.crash_shutdown = hv_machine_crash_shutdown; } const __refconst struct hypervisor_x86 x86_hyper_ms_hyperv = { -- cgit v1.2.3