lkdtm: avoid calling lkdtm_do_action() with spinlock held

lkdtm_do_action() may call sleeping functions like kmalloc(), so do not
call it with spin lock held.

Signed-off-by: WANG Cong <xiyou.wangcong@gmail.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Greg Kroah-Hartman <greg@kroah.com>
Reviewed-by: Dave Young <dyoung@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/misc/lkdtm.c

@@ -354,17 +354,21 @@ static void lkdtm_do_action(enum ctype which)
 static void lkdtm_handler(void)
 {
 	unsigned long flags;
+	bool do_it = false;
 
 	spin_lock_irqsave(&count_lock, flags);
 	count--;
 	printk(KERN_INFO "lkdtm: Crash point %s of type %s hit, trigger in %d rounds\n",
 			cp_name_to_str(cpoint), cp_type_to_str(cptype), count);
 
 	if (count == 0) {
-		lkdtm_do_action(cptype);
+		do_it = true;
 		count = cpoint_count;
 	}
 	spin_unlock_irqrestore(&count_lock, flags);
+
+	if (do_it)
+		lkdtm_do_action(cptype);
 }
 
 static int lkdtm_register_cpoint(enum cname which)