The following commit has been merged into the perf/urgent branch of tip: Commit-ID: 0d39844150546fa1415127c5fbae26db64070dd3 Gitweb: https://git.kernel.org/tip/0d39844150546fa1415127c5fbae26db64070dd3 Author: Kan Liang <kan.liang@xxxxxxxxxxxxxxx> AuthorDate: Fri, 17 Jan 2025 07:19:12 -08:00 Committer: Ingo Molnar <mingo@xxxxxxxxxx> CommitterDate: Tue, 25 Feb 2025 14:54:14 +01:00 perf/core: Fix low freq setting via IOC_PERIOD A low attr::freq value cannot be set via IOC_PERIOD on some platforms. The perf_event_check_period() introduced in: 81ec3f3c4c4d ("perf/x86: Add check_period PMU callback") was intended to check the period, rather than the frequency. A low frequency may be mistakenly rejected by limit_period(). Fix it. Fixes: 81ec3f3c4c4d ("perf/x86: Add check_period PMU callback") Signed-off-by: Kan Liang <kan.liang@xxxxxxxxxxxxxxx> Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> Reviewed-by: Ravi Bangoria <ravi.bangoria@xxxxxxx> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Cc: stable@xxxxxxxxxxxxxxx Link: https://lore.kernel.org/r/20250117151913.3043942-2-kan.liang@xxxxxxxxxxxxxxx Closes: https://lore.kernel.org/lkml/20250115154949.3147-1-ravi.bangoria@xxxxxxx/ --- 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 086d46d..6364319 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -5969,14 +5969,15 @@ 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);
