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From: Adrian Hunter <adrian.hunter@intel.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>,
	Alexander Shishkin <alexander.shishkin@linux.intel.com>,
	Arnaldo Carvalho de Melo <acme@kernel.org>,
	Jiri Olsa <jolsa@kernel.org>, Namhyung Kim <namhyung@kernel.org>,
	Ian Rogers <irogers@google.com>,
	linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org
Subject: [PATCH 0/3] perf/x86/intel/pt: Fix stop/start with no update
Date: Tue, 21 Jul 2026 10:02:51 +0300	[thread overview]
Message-ID: <20260721070254.13557-1-adrian.hunter@intel.com> (raw)

Hi

Here is a fix for Intel PT.

There are 2 preparatory patches with no functional change intended.

The fix is to prevent nesting of perf_aux_output_begin() which
triggers the WARNING in perf_aux_output_begin():

	nest = READ_ONCE(rb->aux_nest);
	/*
	 * Nesting is not supported for AUX area, make sure nested
	 * writers are caught early
	 */
	if (WARN_ON_ONCE(nest))
		goto err_put;

The nesting happens when Intel PT gets throttled.  See the patch for more
details.


Adrian Hunter (3):
      perf/x86/intel/pt: Factor out pt_config_enable()
      perf/x86/intel/pt: Use bitwise access for PERF_HES_STOPPED
      perf/x86/intel/pt: Fix stop/start with no update

 arch/x86/events/intel/pt.c | 96 +++++++++++++++++++++++++++++++---------------
 1 file changed, 65 insertions(+), 31 deletions(-)


Regards
Adrian

             reply	other threads:[~2026-07-21  7:03 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-07-21  7:02 Adrian Hunter [this message]
2026-07-21  7:02 ` [PATCH 1/3] perf/x86/intel/pt: Factor out pt_config_enable() Adrian Hunter
2026-07-21  7:02 ` [PATCH 2/3] perf/x86/intel/pt: Use bitwise access for PERF_HES_STOPPED Adrian Hunter
2026-07-21  7:02 ` [PATCH 3/3] perf/x86/intel/pt: Fix stop/start with no update Adrian Hunter

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