From: Ben Hutchings <[email protected]>
From: Dan Carpenter <[email protected]>
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 <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Acked-by: Peter Zijlstra (Intel) <[email protected]>
Cc: [email protected]
Link: https://lore.kernel.org/r/20201106085205.GA1159983@mwanda
Signed-off-by: Greg Kroah-Hartman <[email protected]>
[bwh: Backported to 4.9: adjust context]
Signed-off-by: Ben Hutchings <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
kernel/futex.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -882,10 +882,12 @@ static void put_pi_state(struct futex_pi
* 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) {
