futex: Cover all PI opcodes with cmpxchg enabled check

Some of the newer futex PI opcodes do not check the cmpxchg enabled
variable and call unconditionally into the handling functions. Cover
all PI opcodes in a separate check.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Darren Hart <dvhart@linux.intel.com>

1 files changed, 13 insertions, 6 deletions

diff --git a/kernel/futex.c b/kernel/futex.c
index ea87f4d2f455..4b1c4b6a339c 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -2629,6 +2629,16 @@ long do_futex(u32 __user *uaddr, int op, u32 val, ktime_t *timeout,
         }
 
         switch (cmd) {
+        case FUTEX_LOCK_PI:
+        case FUTEX_UNLOCK_PI:
+        case FUTEX_TRYLOCK_PI:
+        case FUTEX_WAIT_REQUEUE_PI:
+        case FUTEX_CMP_REQUEUE_PI:
+                if (!futex_cmpxchg_enabled)
+                        return -ENOSYS;
+        }
+
+        switch (cmd) {
         case FUTEX_WAIT:
                 val3 = FUTEX_BITSET_MATCH_ANY;
         case FUTEX_WAIT_BITSET:
@@ -2649,16 +2659,13 @@ long do_futex(u32 __user *uaddr, int op, u32 val, ktime_t *timeout,
                 ret = futex_wake_op(uaddr, flags, uaddr2, val, val2, val3);
                 break;
         case FUTEX_LOCK_PI:
-                if (futex_cmpxchg_enabled)
-                        ret = futex_lock_pi(uaddr, flags, val, timeout, 0);
+                ret = futex_lock_pi(uaddr, flags, val, timeout, 0);
                 break;
         case FUTEX_UNLOCK_PI:
-                if (futex_cmpxchg_enabled)
-                        ret = futex_unlock_pi(uaddr, flags);
+                ret = futex_unlock_pi(uaddr, flags);
                 break;
         case FUTEX_TRYLOCK_PI:
-                if (futex_cmpxchg_enabled)
-                        ret = futex_lock_pi(uaddr, flags, 0, timeout, 1);
+                ret = futex_lock_pi(uaddr, flags, 0, timeout, 1);
                 break;
         case FUTEX_WAIT_REQUEUE_PI:
                 val3 = FUTEX_BITSET_MATCH_ANY;