[patch 08/11] posix-timers: Make per process list RCU safe

From: Thomas Gleixner
Date: Mon Feb 24 2025 - 05:17:01 EST


Preparatory change to remove the sighand locking from the /proc/$PID/timers
iterator.

Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
---
kernel/time/posix-timers.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

--- a/kernel/time/posix-timers.c
+++ b/kernel/time/posix-timers.c
@@ -496,7 +496,7 @@ static int do_timer_create(clockid_t whi
* unmodified signal pointer to make it valid.
*/
WRITE_ONCE(new_timer->it_signal, current->signal);
- hlist_add_head(&new_timer->list, &current->signal->posix_timers);
+ hlist_add_head_rcu(&new_timer->list, &current->signal->posix_timers);
spin_unlock_irq(&current->sighand->siglock);
/*
* After unlocking sighand::siglock @new_timer is subject to
@@ -1072,7 +1072,7 @@ static int posix_timer_delete(struct k_i
unsigned long sig = (unsigned long)timer->it_signal | 1UL;

WRITE_ONCE(timer->it_signal, (struct signal_struct *)sig);
- hlist_del(&timer->list);
+ hlist_del_rcu(&timer->list);
posix_timer_cleanup_ignored(timer);
}