Dump log from current process when required

When dumping a debug log first check that it is safe to create
a new thread and block waiting for it.  If we are in an atomic
context or irqs and disabled it is not safe to sleep and we
must write out of the debug log from the current process.

module/spl/spl-debug.c

@@ -1112,6 +1112,9 @@ void spl_debug_bug(char *file, const char *func, const int line, int flags)
                 /* not reached */
         }
 
+	if (in_atomic() || irqs_disabled())
+		flags |= DL_NOTHREAD;
+
         /* Ensure all debug pages and dumped by current cpu */
          if (spl_debug_panic_on_bug)
                 spl_panic_in_progress = 1;