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 <[email protected]>
Signed-off-by: Vitaly Kuznetsov <[email protected]>
Signed-off-by: K. Y. Srinivasan <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
This commit is contained in:
Vitaly Kuznetsov 2015-08-01 16:08:09 -07:00 • committed by Greg Kroah-Hartman
commit b4370df2b1
3 changed files with 38 additions and 0 deletions

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();