62 lines
2.0 KiB
Diff
62 lines
2.0 KiB
Diff
|
From ad3a4959139317221f6e72f3d69da320ccc218be Mon Sep 17 00:00:00 2001
|
||
|
|
From: Peter Zijlstra <peterz@infradead.org>
|
||
|
|
Date: Wed, 6 Jun 2018 15:31:29 +0200
|
||
|
|
Subject: [PATCH 346/365] futex: Fix OWNER_DEAD fixup
|
||
|
|
|
||
|
|
[ Upstream commit a97cb0e7b3f4c6297fd857055ae8e895f402f501 ]
|
||
|
|
|
||
|
|
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.
|
||
|
|
|
||
|
|
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
|
||
|
|
Reported-by: Dave Jones <davej@codemonkey.org.uk>
|
||
|
|
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
|
||
|
|
Cc: Andrew Morton <akpm@linux-foundation.org>
|
||
|
|
Cc: Linus Torvalds <torvalds@linux-foundation.org>
|
||
|
|
Cc: Paul E. McKenney <paulmck@us.ibm.com>
|
||
|
|
Cc: Peter Zijlstra <peterz@infradead.org>
|
||
|
|
Cc: Thomas Gleixner <tglx@linutronix.de>
|
||
|
|
Fixes: c1e2f0eaf015 ("futex: Avoid violating the 10th rule of futex")
|
||
|
|
Link: http://lkml.kernel.org/r/20180122103947.GD2228@hirez.programming.kicks-ass.net
|
||
|
|
Signed-off-by: Ingo Molnar <mingo@kernel.org>
|
||
|
|
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
|
||
|
|
Signed-off-by: Julia Cartwright <julia@ni.com>
|
||
|
|
---
|
||
|
|
kernel/futex.c | 6 +++---
|
||
|
|
1 file changed, 3 insertions(+), 3 deletions(-)
|
||
|
|
|
||
|
|
diff --git a/kernel/futex.c b/kernel/futex.c
|
||
|
|
index 498a2980e0d7..0279bf7c69b4 100644
|
||
|
|
--- a/kernel/futex.c
|
||
|
|
+++ b/kernel/futex.c
|
||
|
|
@@ -2326,9 +2326,6 @@ static int fixup_pi_state_owner(u32 __user *uaddr, struct futex_q *q,
|
||
|
|
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:
|
||
|
|
@@ -2389,6 +2386,9 @@ static int fixup_pi_state_owner(u32 __user *uaddr, struct futex_q *q,
|
||
|
|
}
|
||
|
|
|
||
|
|
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;
|
||
|
|
--
|
||
|
|
2.28.0
|
||
|
|
|