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-rw-r--r--kernel/futex.c11
1 files changed, 7 insertions, 4 deletions
diff --git a/kernel/futex.c b/kernel/futex.c
index 7ac167683c9f..ede2f1ef8511 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -1025,7 +1025,8 @@ static int attach_to_pi_state(u32 __user *uaddr, u32 uval,
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 *uaddr, u32 uval, struct futex_pi_state *pi_
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 *uaddr, u32 uval, struct futex_pi_state *pi_
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: