6.14-stable review patch. If anyone has any objections, please let me know.
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From: Benjamin Segall bsegall@google.com
[ Upstream commit f99c5bb396b8d1424ed229d1ffa6f596e3b9c36b ]
exit_itimers() loops through every timer in the process to delete it. This requires taking the system-wide hash_lock for each of these timers, and contends with other processes trying to create or delete timers.
When a process creates hundreds of thousands of timers, and then exits while other processes contend with it, this can trigger softlockups on CONFIG_PREEMPT=n.
Add a cond_resched() invocation into the loop to allow the system to make progress.
Signed-off-by: Ben Segall bsegall@google.com Signed-off-by: Thomas Gleixner tglx@linutronix.de Link: https://lore.kernel.org/all/xm2634gg2n23.fsf@google.com Signed-off-by: Sasha Levin sashal@kernel.org --- kernel/time/posix-timers.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/kernel/time/posix-timers.c b/kernel/time/posix-timers.c index 15ed343693101..43b08a04898a8 100644 --- a/kernel/time/posix-timers.c +++ b/kernel/time/posix-timers.c @@ -1107,8 +1107,10 @@ void exit_itimers(struct task_struct *tsk) spin_unlock_irq(&tsk->sighand->siglock);
/* The timers are not longer accessible via tsk::signal */ - while (!hlist_empty(&timers)) + while (!hlist_empty(&timers)) { itimer_delete(hlist_entry(timers.first, struct k_itimer, list)); + cond_resched(); + }
/* * There should be no timers on the ignored list. itimer_delete() has