Patch "futex: Fix OWNER_DEAD fixup" has been added to the 4.14-stable tree

This is a note to let you know that I've just added the patch titled

futex: Fix OWNER_DEAD fixup

to the 4.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
futex-fix-owner_dead-fixup.patch
and it can be found in the queue-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Peter Zijlstra <[email protected]>
Date: Mon, 22 Jan 2018 11:39:47 +0100
Subject: futex: Fix OWNER_DEAD fixup

From: Peter Zijlstra <[email protected]>

commit a97cb0e7b3f4c6297fd857055ae8e895f402f501 upstream.

Both Geert and DaveJ reported that the recent futex commit:

c1e2f0eaf015 ("futex: Avoid violating the 10th rule of futex")

introduced a problem with setting OWNER_DEAD. We set the bit on an uninitialized variable and then entirely optimize it away as a dead-store.

Move the setting of the bit to where it is more useful.

---
 kernel/futex.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

@@ -2311,9 +2311,6 @@ static int fixup_pi_state_owner(u32 __us
 	raw_spin_lock_irq(&pi_state->pi_mutex.wait_lock);
 
 	oldowner = pi_state->owner;
-	/* Owner died? */
-	if (!pi_state->owner)
-		newtid |= FUTEX_OWNER_DIED;
 
 	/*
 	 * We are here because either:

@@ -2374,6 +2371,9 @@ retry:
 	}
 
 	newtid = task_pid_vnr(newowner) | FUTEX_WAITERS;
+	/* Owner died? */
+	if (!pi_state->owner)
+		newtid |= FUTEX_OWNER_DIED;
 
 	if (get_futex_value_locked(&uval, uaddr))
 		goto handle_fault;

Patches currently in stable-queue which might be from [email protected] are

queue-4.14/futex-fix-owner_dead-fixup.patch