futex: fix init order

When the futex init code fails to initialize the futex pseudo file system it
returns early without initializing the hash queues.  Should the boot succeed
then a futex syscall which tries to enqueue a waiter on the hashqueue will
crash due to the unitilialized plist heads.

Initialize the hash queues before the filesystem.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Ingo Molnar <mingo@elte.hu>
Cc: Lennert Buytenhek <buytenh@wantstofly.org>
Cc: Riku Voipio <riku.voipio@movial.fi>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/kernel/futex.c b/kernel/futex.c
index 221f212..c21f667 100644 (file)
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -2145,8 +2145,14 @@ static struct file_system_type futex_fs_type = {
 
 static int __init init(void)
 {
-       int i = register_filesystem(&futex_fs_type);
+       int i;
 
+       for (i = 0; i < ARRAY_SIZE(futex_queues); i++) {
+               plist_head_init(&futex_queues[i].chain, &futex_queues[i].lock);
+               spin_lock_init(&futex_queues[i].lock);
+       }
+
+       i = register_filesystem(&futex_fs_type);
        if (i)
                return i;
 
@@ -2156,10 +2162,6 @@ static int __init init(void)
                return PTR_ERR(futex_mnt);
        }
 
-       for (i = 0; i < ARRAY_SIZE(futex_queues); i++) {
-               plist_head_init(&futex_queues[i].chain, &futex_queues[i].lock);
-               spin_lock_init(&futex_queues[i].lock);
-       }
        return 0;
 }
 __initcall(init);