Bug#1104796: perf r5101c4 counter regression

From	Salvatore Bonaccorso <carnil@debian.org>
Newsgroups	linux.debian.bugs.dist, linux.kernel, linux.debian.kernel
Subject	Bug#1104796: perf r5101c4 counter regression
Date	2025-05-06 21:10 +0200
Message-ID	<KJvPX-1cJ2-7@gated-at.bofh.it> (permalink)
References	<KJtl7-1b1q-1@gated-at.bofh.it> <KJtl7-1b1q-1@gated-at.bofh.it>
Organization	linux.* mail to news gateway

Cross-posted to 3 groups.

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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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Bug#1104796: perf r5101c4 counter regression Salvatore Bonaccorso <carnil@debian.org> - 2025-05-06 21:10 +0200
  Bug#1104796: perf r5101c4 counter regression Namhyung Kim <namhyung@kernel.org> - 2025-05-08 23:10 +0200

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