blob: 8b06ae678c45a895f94f594603cba43acc10ea35 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
|
From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date: Thu, 4 Jul 2024 19:03:35 +0200
Subject: [PATCH 1/7] perf: Move irq_work_queue() where the event is prepared.
Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.10/older/patches-6.10.2-rt14.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 <elver@google.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Link: https://lore.kernel.org/r/20240704170424.1466941-2-bigeasy@linutronix.de
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
kernel/events/core.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -9738,6 +9738,11 @@ static int __perf_event_overflow(struct
if (!event->pending_sigtrap) {
event->pending_sigtrap = pending_id;
local_inc(&event->ctx->nr_pending);
+
+ event->pending_addr = 0;
+ if (valid_sample && (data->sample_flags & PERF_SAMPLE_ADDR))
+ event->pending_addr = data->addr;
+ irq_work_queue(&event->pending_irq);
} else if (event->attr.exclude_kernel && valid_sample) {
/*
* Should not be able to return to user space without
@@ -9753,11 +9758,6 @@ static int __perf_event_overflow(struct
*/
WARN_ON_ONCE(event->pending_sigtrap != pending_id);
}
-
- 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);
|
