From: Sebastian Andrzej Siewior Date: Tue, 12 Mar 2024 19:01:49 +0100 Subject: [PATCH 1/4] perf: Move irq_work_queue() where the event is prepared. Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.8/older/patches-6.8.2-rt11.tar.xz Only if perf_event::pending_sigtrap is zero, the irq_work accounted by increminging perf_event::nr_pending. The member perf_event::pending_addr might be overwritten by a subsequent event if the signal was not yet delivered and is expected. The irq_work will not be enqeueued again because it has a check to be only enqueued once. Move irq_work_queue() to where the counter is incremented and perf_event::pending_sigtrap is set to make it more obvious that the irq_work is scheduled once. Tested-by: Marco Elver Tested-by: Arnaldo Carvalho de Melo Reported-by: Arnaldo Carvalho de Melo Link: https://lore.kernel.org/r/20240312180814.3373778-2-bigeasy@linutronix.de Signed-off-by: Sebastian Andrzej Siewior --- kernel/events/core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -9595,6 +9595,7 @@ static int __perf_event_overflow(struct if (!event->pending_sigtrap) { event->pending_sigtrap = pending_id; local_inc(&event->ctx->nr_pending); + irq_work_queue(&event->pending_irq); } else if (event->attr.exclude_kernel && valid_sample) { /* * Should not be able to return to user space without @@ -9614,7 +9615,6 @@ static int __perf_event_overflow(struct event->pending_addr = 0; if (valid_sample && (data->sample_flags & PERF_SAMPLE_ADDR)) event->pending_addr = data->addr; - irq_work_queue(&event->pending_irq); } READ_ONCE(event->overflow_handler)(event, data, regs);