From: Kan Liang kan.liang@linux.intel.com
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@amd.com/ Signed-off-by: Kan Liang kan.liang@linux.intel.com Cc: Jiri Olsa jolsa@redhat.com Cc: Ravi Bangoria ravi.bangoria@amd.com Cc: stable@vger.kernel.org --- 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);