[PATCH] additional might_sleep checks

- Dave says that lock_sock() inside locks is a popular bug.  Put a
  check there.

- Also in wait_for_completion().

- Add the text "Debug" to the warning message so people are less
  likely to think that they've oopsed.

include/net/sock.h

@@ -309,7 +309,8 @@ static __inline__ void sock_prot_dec_use(struct proto *prot)
 extern void __lock_sock(struct sock *sk);
 extern void __release_sock(struct sock *sk);
 #define lock_sock(__sk) \
-do {	spin_lock_bh(&((__sk)->lock.slock)); \
+do {	might_sleep(); \
+	spin_lock_bh(&((__sk)->lock.slock)); \
 	if ((__sk)->lock.users != 0) \
 		__lock_sock(__sk); \
 	(__sk)->lock.users = 1; \

kernel/sched.c

@@ -1163,6 +1163,7 @@ void complete(struct completion *x)
 
 void wait_for_completion(struct completion *x)
 {
+	might_sleep();
 	spin_lock_irq(&x->wait.lock);
 	if (!x->done) {
 		DECLARE_WAITQUEUE(wait, current);
@@ -2158,7 +2159,7 @@ void __might_sleep(char *file, int line)
 		if (time_before(jiffies, prev_jiffy + HZ))
 			return;
 		prev_jiffy = jiffies;
-		printk("Sleeping function called from illegal"
+		printk(KERN_ERR "Debug: sleeping function called from illegal"
 				" context at %s:%d\n", file, line);
 		dump_stack();
 	}