4.19.94-rt39-rc2 stable review patch. If anyone has any objections, please let me know. ------------------ From: Julien Grall <julien.grall@xxxxxxx> [ Upstream commit cef1b87f98823af923a386f3f69149acb212d4a1 ] As tglx puts it: |If base == migration_base then there is no point to lock soft_expiry_lock |simply because the timer is not executing the callback in soft irq context |and the whole lock/unlock dance can be avoided. Furthermore, all the path leading to hrtimer_grab_expiry_lock() assumes timer->base and timer->base->cpu_base are always non-NULL. So it is safe to remove the NULL checks here. Signed-off-by: Julien Grall <julien.grall@xxxxxxx> Link: https://lkml.kernel.org/r/alpine.DEB.2.21.1908211557420.2223@xxxxxxxxxxxxxxxxxxxxxxx Signed-off-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx> [bigeasy: rewrite changelog] Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx> --- kernel/time/hrtimer.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c index 49d20fe8570f..1a5167c68310 100644 --- a/kernel/time/hrtimer.c +++ b/kernel/time/hrtimer.c @@ -943,7 +943,7 @@ void hrtimer_grab_expiry_lock(const struct hrtimer *timer) { struct hrtimer_clock_base *base = READ_ONCE(timer->base); - if (timer->is_soft && base && base->cpu_base) { + if (timer->is_soft && base != &migration_base) { spin_lock(&base->cpu_base->softirq_expiry_lock); spin_unlock(&base->cpu_base->softirq_expiry_lock); } -- 2.24.1
