Commit 42d35d48 authored by Darren Hart's avatar Darren Hart Committed by Ingo Molnar
Browse files

futex: make futex_(get|put)_key() calls symmetric 



Impact: cleanup

This patch makes the calls to futex_get_key_refs() and futex_drop_key_refs()
explicitly symmetric by only "putting" keys we successfully "got".  Also
cleanup a couple return points that didn't "put" after a successful "get".

Build and boot tested on an x86_64 system.

Signed-off-by: default avatarDarren Hart <dvhltc@us.ibm.com>
Cc: <stable@kernel.org>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent b5686363

kernel/futex.c

+36 −31
Original line number Diff line number Diff line
@@ -723,8 +723,8 @@ static int futex_wake(u32 __user *uaddr, int fshared, int nr_wake, u32 bitset) 
	}



	spin_unlock(&hb->lock);

out:

	put_futex_key(fshared, &key);

out:

	return ret;

}
@@ -748,7 +748,7 @@ retryfull: 
		goto out;

	ret = get_futex_key(uaddr2, fshared, &key2);

	if (unlikely(ret != 0))

		goto out;

		goto out_put_key1;



	hb1 = hash_futex(&key1);

	hb2 = hash_futex(&key2);
@@ -770,12 +770,12 @@ retry: 
		 * but we might get them from range checking

		 */

		ret = op_ret;

		goto out;

		goto out_put_keys;

#endif



		if (unlikely(op_ret != -EFAULT)) {

			ret = op_ret;

			goto out;

			goto out_put_keys;

		}



		/*
@@ -789,7 +789,7 @@ retry: 
			ret = futex_handle_fault((unsigned long)uaddr2,

						 attempt);

			if (ret)

				goto out;

				goto out_put_keys;

			goto retry;

		}
@@ -827,10 +827,11 @@ retry: 
	spin_unlock(&hb1->lock);

	if (hb1 != hb2)

		spin_unlock(&hb2->lock);

out:

out_put_keys:

	put_futex_key(fshared, &key2);

out_put_key1:

	put_futex_key(fshared, &key1);



out:

	return ret;

}
@@ -853,7 +854,7 @@ static int futex_requeue(u32 __user *uaddr1, int fshared, u32 __user *uaddr2, 
		goto out;

	ret = get_futex_key(uaddr2, fshared, &key2);

	if (unlikely(ret != 0))

		goto out;

		goto out_put_key1;



	hb1 = hash_futex(&key1);

	hb2 = hash_futex(&key2);
@@ -875,7 +876,7 @@ static int futex_requeue(u32 __user *uaddr1, int fshared, u32 __user *uaddr2, 
			if (!ret)

				goto retry;



			return ret;

			goto out_put_keys;

		}

		if (curval != *cmpval) {

			ret = -EAGAIN;
@@ -920,9 +921,11 @@ out_unlock: 
	while (--drop_count >= 0)

		drop_futex_key_refs(&key1);



out:

out_put_keys:

	put_futex_key(fshared, &key2);

out_put_key1:

	put_futex_key(fshared, &key1);

out:

	return ret;

}
@@ -1169,7 +1172,7 @@ static int futex_wait(u32 __user *uaddr, int fshared, 
	q.key = FUTEX_KEY_INIT;

	ret = get_futex_key(uaddr, fshared, &q.key);

	if (unlikely(ret != 0))

		goto out_release_sem;

		goto out;



	hb = queue_lock(&q);
@@ -1197,6 +1200,7 @@ static int futex_wait(u32 __user *uaddr, int fshared, 


	if (unlikely(ret)) {

		queue_unlock(&q, hb);

		put_futex_key(fshared, &q.key);



		ret = get_user(uval, uaddr);
@@ -1206,7 +1210,7 @@ static int futex_wait(u32 __user *uaddr, int fshared, 
	}

	ret = -EWOULDBLOCK;

	if (uval != val)

		goto out_unlock_release_sem;

		goto out_unlock_put_key;



	/* Only actually queue if *uaddr contained val.  */

	queue_me(&q, hb);
@@ -1298,11 +1302,11 @@ static int futex_wait(u32 __user *uaddr, int fshared, 
		return -ERESTART_RESTARTBLOCK;

	}



 out_unlock_release_sem:

out_unlock_put_key:

	queue_unlock(&q, hb);



 out_release_sem:

	put_futex_key(fshared, &q.key);



out:

	return ret;

}
@@ -1355,7 +1359,7 @@ static int futex_lock_pi(u32 __user *uaddr, int fshared, 
	q.key = FUTEX_KEY_INIT;

	ret = get_futex_key(uaddr, fshared, &q.key);

	if (unlikely(ret != 0))

		goto out_release_sem;

		goto out;



retry_unlocked:

	hb = queue_lock(&q);
@@ -1381,14 +1385,14 @@ static int futex_lock_pi(u32 __user *uaddr, int fshared, 
	 */

	if (unlikely((curval & FUTEX_TID_MASK) == task_pid_vnr(current))) {

		ret = -EDEADLK;

		goto out_unlock_release_sem;

		goto out_unlock_put_key;

	}



	/*

	 * Surprise - we got the lock. Just return to userspace:

	 */

	if (unlikely(!curval))

		goto out_unlock_release_sem;

		goto out_unlock_put_key;



	uval = curval;
@@ -1424,7 +1428,7 @@ static int futex_lock_pi(u32 __user *uaddr, int fshared, 
	 * We took the lock due to owner died take over.

	 */

	if (unlikely(lock_taken))

		goto out_unlock_release_sem;

		goto out_unlock_put_key;



	/*

	 * We dont have the lock. Look up the PI state (or create it if
@@ -1463,7 +1467,7 @@ static int futex_lock_pi(u32 __user *uaddr, int fshared, 
				goto retry_locked;

			}

		default:

			goto out_unlock_release_sem;

			goto out_unlock_put_key;

		}

	}
@@ -1554,11 +1558,12 @@ static int futex_lock_pi(u32 __user *uaddr, int fshared, 
		destroy_hrtimer_on_stack(&to->timer);

	return ret != -EINTR ? ret : -ERESTARTNOINTR;



 out_unlock_release_sem:

out_unlock_put_key:

	queue_unlock(&q, hb);



 out_release_sem:

out_put_key:

	put_futex_key(fshared, &q.key);

out:

	if (to)

		destroy_hrtimer_on_stack(&to->timer);

	return ret;
@@ -1576,7 +1581,7 @@ static int futex_lock_pi(u32 __user *uaddr, int fshared, 
	if (attempt++) {

		ret = futex_handle_fault((unsigned long)uaddr, attempt);

		if (ret)

			goto out_release_sem;

			goto out_put_key;

		goto retry_unlocked;

	}
@@ -1668,9 +1673,9 @@ retry_unlocked: 


out_unlock:

	spin_unlock(&hb->lock);

out:

	put_futex_key(fshared, &key);



out:

	return ret;



pi_faulted:

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