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>

1 files changed, 7 insertions, 5 deletions

diff --git a/kernel/futex.c b/kernel/futex.c
index 221f2128a437..c21f667c63f6 100644
--- 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);