From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751817AbbFYJ7H (ORCPT ); Thu, 25 Jun 2015 05:59:07 -0400 Received: from mx1.redhat.com ([209.132.183.28]:59647 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752880AbbFYJ6Z (ORCPT ); Thu, 25 Jun 2015 05:58:25 -0400 From: Vitaly Kuznetsov To: devel@linuxdriverproject.org Cc: linux-kernel@vger.kernel.org, kexec@lists.infradead.org, Eric Biederman , x86@kernel.org, "H. Peter Anvin" , Ingo Molnar , Thomas Gleixner , Haiyang Zhang , "K. Y. Srinivasan" , Olaf Hering , Greg KH Subject: [PATCH v3 5/5] Drivers: hv: vmbus: add special crash handler Date: Thu, 25 Jun 2015 11:58:06 +0200 Message-Id: <1435226286-24842-6-git-send-email-vkuznets@redhat.com> In-Reply-To: <1435226286-24842-1-git-send-email-vkuznets@redhat.com> References: <1435226286-24842-1-git-send-email-vkuznets@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 --- arch/x86/include/asm/mshyperv.h | 2 ++ arch/x86/kernel/cpu/mshyperv.c | 22 ++++++++++++++++++++++ drivers/hv/vmbus_drv.c | 14 ++++++++++++++ 3 files changed, 38 insertions(+) diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h index d3db910..d02f9c9 100644 --- a/arch/x86/include/asm/mshyperv.h +++ b/arch/x86/include/asm/mshyperv.h @@ -22,4 +22,6 @@ void hv_remove_vmbus_irq(void); void hv_setup_kexec_handler(void (*handler)(void)); void hv_remove_kexec_handler(void); +void hv_setup_crash_handler(void (*handler)(struct pt_regs *regs)); +void hv_remove_crash_handler(void); #endif diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c index 09911aa..1a6e742 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); @@ -85,6 +86,18 @@ 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) @@ -94,6 +107,14 @@ 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; @@ -167,6 +188,7 @@ 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 = { diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c index 31748a2..1ed9b32 100644 --- a/drivers/hv/vmbus_drv.c +++ b/drivers/hv/vmbus_drv.c @@ -1071,6 +1071,18 @@ static void hv_kexec_handler(void) hv_cleanup(); }; +static void hv_crash_handler(struct pt_regs *regs) +{ + vmbus_initiate_unload(); + /* + * In crash handler we can't schedule synic cleanup for all CPUs, + * doing the cleanup for current CPU only. This should be sufficient + * for kdump. + */ + hv_synic_cleanup(NULL); + hv_cleanup(); +}; + static int __init hv_acpi_init(void) { int ret, t; @@ -1104,6 +1116,7 @@ static int __init hv_acpi_init(void) goto cleanup; hv_setup_kexec_handler(hv_kexec_handler); + hv_setup_crash_handler(hv_crash_handler); return 0; @@ -1118,6 +1131,7 @@ static void __exit vmbus_exit(void) int cpu; hv_remove_kexec_handler(); + hv_remove_crash_handler(); vmbus_connection.conn_state = DISCONNECTED; hv_synic_clockevents_cleanup(); vmbus_disconnect(); -- 2.4.2