From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.13]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 29E96495535; Wed, 29 Jul 2026 13:36:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.13 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785332215; cv=none; b=fkDNRw8xCJCUo+mz4Fb5gnRndCKjsaJy/a77KaHkU0tkpuVYeS7xiEgwrTK4zfEmG9D5lxVyQL9k4rZLznrMtGD4J4a7GH7A5yA+QNc2fH6MG1AUldtXL3vie+wAUGCHTiPQMPeDAZavW+FsC19XzWD8jKEnjr/EGGCLkn3SYJE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785332215; c=relaxed/simple; bh=JcF5jgLPEItViI1aMlbMe7iPgrnakBvzJzKgmdRqaEM=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=pe2SXiNCznq7sq9b0xpxOFipj9aoVM01QEr284eRPtKaF8fVrz0pvGXSzf/dgJLAVZJJNO2ESqiLGAY6c+eVPNe6pPklh43twNRrYIwKX04gG4KfzGn/by60A69M2/mqtqcEWFpb9RWbp0LbP27cR39YEqh/QEkW5n2CzcoPcJk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com; spf=pass smtp.mailfrom=intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=Lo4D0GvU; arc=none smtp.client-ip=198.175.65.13 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="Lo4D0GvU" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1785332208; x=1816868208; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=JcF5jgLPEItViI1aMlbMe7iPgrnakBvzJzKgmdRqaEM=; b=Lo4D0GvU1BxIqZTaZQObEYzM5j7BMbP2Edbl+1eFILy/5RHzjt2n8gMH fBx1rBNEEOCCdSiOAyxZqd2Pl+n3C86eOuGAzZwxGVZekFTWMeblyQRT/ WjiHJAKPNuoiNspv+E3lL75fqG35zIjWiOP/lcd+UegXB3+BUGVLrJRVa q6bFjBfjswA5P+c7tmW/ymxbdfie2OmnscDglKq0J/1SPATEOv/tAnDOS yb2+EUT6EAcf3un+GJtY6ZtL5jXGhEKwt0cOCl9zZweB+5Jp4pJTv32OR PhpakKahG/G5CAMpFfbf3FU596bWHWJfpzkqAmQo0Tcd69EaIrKRIT3DX w==; X-CSE-ConnectionGUID: NfuoWnqEQWCnNhnApTUVxQ== X-CSE-MsgGUID: cJOLDfILQpSN/9OXMUDSAA== X-IronPort-AV: E=McAfee;i="6800,10657,11859"; a="97093718" X-IronPort-AV: E=Sophos;i="6.25,192,1779174000"; d="scan'208";a="97093718" Received: from orviesa001.jf.intel.com ([10.64.159.141]) by orvoesa105.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 29 Jul 2026 06:36:24 -0700 X-CSE-ConnectionGUID: FFzJcIC6T9Wt9vRdV66jKg== X-CSE-MsgGUID: 2cuftd+GS22bpskHkr6geA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.25,192,1779174000"; d="scan'208";a="298228740" Received: from ly-workstation.sh.intel.com (HELO ly-workstation) ([10.239.182.64]) by smtpauth.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 29 Jul 2026 06:36:22 -0700 Date: Wed, 29 Jul 2026 21:36:18 +0800 From: "Lai, Yi" To: Adrian Hunter Cc: Peter Zijlstra , Ingo Molnar , Alexander Shishkin , Arnaldo Carvalho de Melo , Jiri Olsa , Namhyung Kim , Ian Rogers , linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org Subject: Re: [PATCH 0/3] perf/x86/intel/pt: Fix stop/start with no update Message-ID: References: <20260721070254.13557-1-adrian.hunter@intel.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260721070254.13557-1-adrian.hunter@intel.com> On Tue, Jul 21, 2026 at 10:02:51AM +0300, Adrian Hunter wrote: > 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(-) > > Applied this series on top of v7.2-rc5. After forcing perf throttling, the WARNING in perf_aux_output_begin no longer appears. Tested-by: Yi Lai > Regards > Adrian