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perf/core: Fix low freq setting via IOC_PERIOD

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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@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Ravi Bangoria <ravi.bangoria@amd.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20250117151913.3043942-2-kan.liang@linux.intel.com
Closes: https://lore.kernel.org/lkml/20250115154949.3147-1-ravi.bangoria@amd.com/
This commit is contained in:
Kan Liang 2025-01-17 07:19:12 -08:00 committed by Ingo Molnar
parent 88ec7eedbb
commit 0d39844150
1 changed files with 9 additions and 8 deletions
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17
kernel/events/core.c
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@ -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);