From: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
commit 1e106aa3509b86738769775969822ffc1ec21bf4 upstream.
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() variant so that IRQs are restored to the original state
instead of being enabled unconditionally.
Fixes: 153fbd1226fb ("futex: Fix more put_pi_state() vs. exit_pi_state_list() races")
Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Acked-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Link: https://lore.kernel.org/r/20201106085205.GA1159983@mwanda
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
[bwh: Backported to 4.9: adjust context]
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
kernel/futex.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/kernel/futex.c b/kernel/futex.c
index 855dae277f83..0015c14ac2c0 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -882,10 +882,12 @@ static void put_pi_state(struct futex_pi_state *pi_state)
* and has cleaned up the pi_state already
*/
if (pi_state->owner) {
- raw_spin_lock_irq(&pi_state->pi_mutex.wait_lock);
+ unsigned long flags;
+
+ raw_spin_lock_irqsave(&pi_state->pi_mutex.wait_lock, flags);
pi_state_update_owner(pi_state, NULL);
rt_mutex_proxy_unlock(&pi_state->pi_mutex);
- 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) {
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