56 lines
1.8 KiB
Diff
56 lines
1.8 KiB
Diff
From: Peter Zijlstra <peterz@infradead.org>
|
|
Date: Fri, 7 Apr 2017 09:04:07 +0200
|
|
Subject: [PATCH 2/4] futex: Fix small (and harmless looking) inconsistencies
|
|
Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.11/older/patches-4.11.9-rt7.tar.xz
|
|
|
|
During (post-commit) review Darren spotted a few minor things. One
|
|
(harmless AFAICT) type inconsistency and a comment that wasn't as
|
|
clear as hoped.
|
|
|
|
Reported-by: Darren Hart (VMWare) <dvhart@infradead.org>
|
|
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
|
|
Reviewed-by: Darren Hart (VMware) <dvhart@infradead.org>
|
|
Cc: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Cc: Peter Zijlstra <peterz@infradead.org>
|
|
Cc: Thomas Gleixner <tglx@linutronix.de>
|
|
Cc: linux-kernel@vger.kernel.org
|
|
Signed-off-by: Ingo Molnar <mingo@kernel.org>
|
|
---
|
|
kernel/futex.c | 11 +++++++----
|
|
1 file changed, 7 insertions(+), 4 deletions(-)
|
|
|
|
--- a/kernel/futex.c
|
|
+++ b/kernel/futex.c
|
|
@@ -1025,7 +1025,8 @@ static int attach_to_pi_state(u32 __user
|
|
struct futex_pi_state **ps)
|
|
{
|
|
pid_t pid = uval & FUTEX_TID_MASK;
|
|
- int ret, uval2;
|
|
+ u32 uval2;
|
|
+ int ret;
|
|
|
|
/*
|
|
* Userspace might have messed up non-PI and PI futexes [3]
|
|
@@ -1441,6 +1442,11 @@ static int wake_futex_pi(u32 __user *uad
|
|
if (ret)
|
|
goto out_unlock;
|
|
|
|
+ /*
|
|
+ * This is a point of no return; once we modify the uval there is no
|
|
+ * going back and subsequent operations must not fail.
|
|
+ */
|
|
+
|
|
raw_spin_lock(&pi_state->owner->pi_lock);
|
|
WARN_ON(list_empty(&pi_state->list));
|
|
list_del_init(&pi_state->list);
|
|
@@ -1452,9 +1458,6 @@ static int wake_futex_pi(u32 __user *uad
|
|
pi_state->owner = new_owner;
|
|
raw_spin_unlock(&new_owner->pi_lock);
|
|
|
|
- /*
|
|
- * We've updated the uservalue, this unlock cannot fail.
|
|
- */
|
|
postunlock = __rt_mutex_futex_unlock(&pi_state->pi_mutex, &wake_q);
|
|
|
|
out_unlock:
|