From: Thomas Gleixner <tglx@linutronix.de>
Date: Wed, 15 Feb 2012 11:08:34 +0000 (+0100)
Subject: futex: Cover all PI opcodes with cmpxchg enabled check
X-Git-Tag: firefly_0821_release~7541^2~1535
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=be455802bf55a051bb467b22ad26653a0e78bc61;p=firefly-linux-kernel-4.4.55.git

futex: Cover all PI opcodes with cmpxchg enabled check

commit 59263b513c11398cd66a52d4c5b2b118ce1e0359 upstream.

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: Peter Zijlstra <peterz@infradead.org>
Cc: Darren Hart <dvhart@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/kernel/futex.c b/kernel/futex.c
index 6487e4cb9935..a2a01ef0ee3c 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -2640,6 +2640,16 @@ long do_futex(u32 __user *uaddr, int op, u32 val, ktime_t *timeout,
 			return -ENOSYS;
 	}
 
+	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;
@@ -2661,16 +2671,13 @@ 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;