[PATCH v2 1/4] perf: Move irq_work_queue() where the event is prepared.

Sebastian Andrzej Siewior
2024-03-12T18:08:20Z

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.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
kernel/events/core.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/events/core.c b/kernel/events/core.c
index f0f0f71213a1d..c7a0274c662c8 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -9595,6 +9595,7 @@ static int __perf_event_overflow(struct perf_event *event,
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 perf_event *event,
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);
--
2.43.0