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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 <kys@microsoft.com>
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Vitaly Kuznetsov 2015-08-01 16:08:09 -07:00 committed by Greg Kroah-Hartman
parent d7646eaa76
commit b4370df2b1
3 changed files with 38 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
arch/x86/include/asm/mshyperv.h
View File

@ -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

22
arch/x86/kernel/cpu/mshyperv.c
View File

@ -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 = {

14
drivers/hv/vmbus_drv.c
View File

@ -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();