Bug#1104796: perf r5101c4 counter regression
- To: Pasi Kallinen <paxed@alt.org>, 1104796@bugs.debian.org, Peter Zijlstra <peterz@infradead.org>, Ingo Molnar <mingo@redhat.com>, Arnaldo Carvalho de Melo <acme@kernel.org>, Namhyung Kim <namhyung@kernel.org>
- Cc: linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org, regressions@lists.linux.dev, Debian Bug Tracking System <submit@bugs.debian.org>
- Subject: Bug#1104796: perf r5101c4 counter regression
- From: Salvatore Bonaccorso <carnil@debian.org>
- Date: Tue, 6 May 2025 21:02:20 +0200
- Message-id: <[🔎] aBpcvG2yBtrrTie-@eldamar.lan>
- Reply-to: Salvatore Bonaccorso <carnil@debian.org>, 1104796@bugs.debian.org
- In-reply-to: <[🔎] 174654831962.2704.6099474499200154093.reportbug@deveel>
- References: <[🔎] 174654831962.2704.6099474499200154093.reportbug@deveel> <[🔎] 174654831962.2704.6099474499200154093.reportbug@deveel>
Hi,
Pasi Kallinen reported in Debian a regression with perf r5101c4
counter, initially it was found in
https://github.com/rr-debugger/rr/issues/3949 but said to be a kernel
problem.
On Tue, May 06, 2025 at 07:18:39PM +0300, Pasi Kallinen wrote:
> Package: src:linux
> Version: 6.12.25-1
> Severity: normal
> X-Debbugs-Cc: debian-amd64@lists.debian.org, paxed@alt.org
> User: debian-amd64@lists.debian.org
> Usertags: amd64
>
> Dear Maintainer,
>
> perf stat -e r5101c4 true
>
> reports "not supported".
>
> The counters worked in kernel 6.11.10.
>
> I first noticed this not working when updating to 6.12.22.
> Booting back to 6.11.10, the counters work correctly.
Does this ring a bell?
Would you be able to bisect the changes to identify where the
behaviour changed?
Regards,
Salvatore
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