The patch below does not apply to the 5.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y git checkout FETCH_HEAD git cherry-pick -x 88ec7eedbbd21cad38707620ad6c48a4e9a87c18 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2025030424-striking-boxing-7eb2@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..

Possible dependencies:

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 88ec7eedbbd21cad38707620ad6c48a4e9a87c18 Mon Sep 17 00:00:00 2001 From: Kan Liang kan.liang@linux.intel.com Date: Fri, 17 Jan 2025 07:19:11 -0800 Subject: [PATCH] perf/x86: Fix low freqency setting issue

Perf doesn't work at low frequencies:

$ perf record -e cpu_core/instructions/ppp -F 120 Error: The sys_perf_event_open() syscall returned with 22 (Invalid argument) for event (cpu_core/instructions/ppp). "dmesg | grep -i perf" may provide additional information.

The limit_period() check avoids a low sampling period on a counter. It doesn't intend to limit the frequency.

The check in the x86_pmu_hw_config() should be limited to non-freq mode. The attr.sample_period and attr.sample_freq are union. The attr.sample_period should not be used to indicate the frequency mode.

Fixes: c46e665f0377 ("perf/x86: Add INST_RETIRED.ALL workarounds") 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/20250117151913.3043942-1-kan.liang@linux.intel.com Closes: https://lore.kernel.org/lkml/20250115154949.3147-1-ravi.bangoria@amd.com/

diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c index 8f218ac0d445..2092d615333d 100644 --- a/arch/x86/events/core.c +++ b/arch/x86/events/core.c @@ -628,7 +628,7 @@ int x86_pmu_hw_config(struct perf_event *event) if (event->attr.type == event->pmu->type) event->hw.config |= x86_pmu_get_event_config(event);

- if (event->attr.sample_period && x86_pmu.limit_period) { + if (!event->attr.freq && x86_pmu.limit_period) { s64 left = event->attr.sample_period; x86_pmu.limit_period(event, &left); if (left > event->attr.sample_period)