Commit 94ffac5d authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar

futex: Fix small (and harmless looking) inconsistencies

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: default avatarDarren Hart (VMWare) <dvhart@infradead.org>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: default avatarDarren 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: default avatarIngo Molnar <mingo@kernel.org>
parent 97181f9b
...@@ -1025,7 +1025,8 @@ static int attach_to_pi_state(u32 __user *uaddr, u32 uval, ...@@ -1025,7 +1025,8 @@ static int attach_to_pi_state(u32 __user *uaddr, u32 uval,
struct futex_pi_state **ps) struct futex_pi_state **ps)
{ {
pid_t pid = uval & FUTEX_TID_MASK; 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] * Userspace might have messed up non-PI and PI futexes [3]
...@@ -1441,6 +1442,11 @@ static int wake_futex_pi(u32 __user *uaddr, u32 uval, struct futex_pi_state *pi_ ...@@ -1441,6 +1442,11 @@ static int wake_futex_pi(u32 __user *uaddr, u32 uval, struct futex_pi_state *pi_
if (ret) if (ret)
goto out_unlock; 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); raw_spin_lock(&pi_state->owner->pi_lock);
WARN_ON(list_empty(&pi_state->list)); WARN_ON(list_empty(&pi_state->list));
list_del_init(&pi_state->list); list_del_init(&pi_state->list);
...@@ -1452,9 +1458,6 @@ static int wake_futex_pi(u32 __user *uaddr, u32 uval, struct futex_pi_state *pi_ ...@@ -1452,9 +1458,6 @@ static int wake_futex_pi(u32 __user *uaddr, u32 uval, struct futex_pi_state *pi_
pi_state->owner = new_owner; pi_state->owner = new_owner;
raw_spin_unlock(&new_owner->pi_lock); 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); postunlock = __rt_mutex_futex_unlock(&pi_state->pi_mutex, &wake_q);
out_unlock: out_unlock:
......
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