From: Kan Liang <kan.liang@xxxxxxxxxxxxxxx>
A low freq cannot be set via IOC_PERIOD on some platforms.
The perf_event_check_period() introduced in commit 81ec3f3c4c4d
("perf/x86: Add check_period PMU callback") intended to check the
period, rather than the freq. A low freq may be mistakenly rejected by
the limit_period().
Fixes: 81ec3f3c4c4d ("perf/x86: Add check_period PMU callback")
Closes: https://lore.kernel.org/lkml/20250115154949.3147-1-ravi.bangoria@xxxxxxx/
Signed-off-by: Kan Liang <kan.liang@xxxxxxxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Ravi Bangoria <ravi.bangoria@xxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
---
kernel/events/core.c | 17 +++++++++--------
1 file changed, 9 insertions(+), 8 deletions(-)
diff --git a/kernel/events/core.c b/kernel/events/core.c
index f91ba29048ce..a9a04d4f3619 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -5960,14 +5960,15 @@ static int _perf_event_period(struct perf_event *event, u64 value)
if (!value)
return -EINVAL;
- if (event->attr.freq && value > sysctl_perf_event_sample_rate)
- return -EINVAL;
-
- if (perf_event_check_period(event, value))
- return -EINVAL;
-
- if (!event->attr.freq && (value & (1ULL << 63)))
- return -EINVAL;
+ if (event->attr.freq) {
+ if (value > sysctl_perf_event_sample_rate)
+ return -EINVAL;
+ } else {
+ if (perf_event_check_period(event, value))
+ return -EINVAL;
+ if (value & (1ULL << 63))
+ return -EINVAL;
+ }
event_function_call(event, __perf_event_period, &value);
--
2.38.1
