[PATCH] futex: Don't enable IRQs unconditionally in put_pi_state()

[Dan Carpenter]

The exit_pi_state_list() function calls put_pi_state() with IRQs
disabled and is not expecting that IRQs will be enabled inside the
function.  Use the _irqsave() so that IRQs are restored to the original
state instead of enabled unconditionally.

Fixes: 153fbd1226fb ("futex: Fix more put_pi_state() vs. exit_pi_state_list() 
races")
Signed-off-by: Dan Carpenter <dan.carpen...@oracle.com>
---
This is from static analysis and not tested.  I am not very familiar
with futex code.

 kernel/futex.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/kernel/futex.c b/kernel/futex.c
index f8614ef4ff31..ca84745713bc 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -788,8 +788,9 @@ static void put_pi_state(struct futex_pi_state *pi_state)
         */
        if (pi_state->owner) {
                struct task_struct *owner;
+               unsigned long flags;
 
-               raw_spin_lock_irq(&pi_state->pi_mutex.wait_lock);
+               raw_spin_lock_irqsave(&pi_state->pi_mutex.wait_lock, flags);
                owner = pi_state->owner;
                if (owner) {
                        raw_spin_lock(&owner->pi_lock);
@@ -797,7 +798,7 @@ static void put_pi_state(struct futex_pi_state *pi_state)
                        raw_spin_unlock(&owner->pi_lock);
                }
                rt_mutex_proxy_unlock(&pi_state->pi_mutex, owner);
-               raw_spin_unlock_irq(&pi_state->pi_mutex.wait_lock);
+               raw_spin_unlock_irqrestore(&pi_state->pi_mutex.wait_lock, 
flags);
        }
 
        if (current->pi_state_cache) {
-- 
2.28.0