Drivers: hv: avoid vfree() on crash

When we crash from NMI context (e.g. after NMI injection from host when
'sysctl -w kernel.unknown_nmi_panic=1' is set) we hit

    kernel BUG at mm/vmalloc.c:1530!

as vfree() is denied. While the issue could be solved with in_nmi() check
instead I opted for skipping vfree on all sorts of crashes to reduce the
amount of work which can cause consequent crashes. We don't really need to
free anything on crash.

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>

drivers/hv/hyperv_vmbus.h

@@ -495,7 +495,7 @@ struct hv_ring_buffer_debug_info {
 
 extern int hv_init(void);
 
-extern void hv_cleanup(void);
+extern void hv_cleanup(bool crash);
 
 extern int hv_post_message(union hv_connection_id connection_id,
 			 enum hv_message_type message_type,