From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=217.140.110.172 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794582953; b=lf05O3XXn3K9iF5wnq6/i89PFQoIMu4TEiVuIgv7rx+C2N+2KDYHwUetn3wjs9JGnU/C 3dG/SKCYVEWJGMhfnl/HnvsIu+xY7i9y+HpY+SufeZWVuaoL6ZnCNffrhwoS7WI551keB e+pdGIyIvRs0kQAqg4l3D6YH4fmPhz1mKd6PkqH7wa3iEEOJyq9Nw4Zzbp2dBsoSxIJzD WwabfgTSWb+ddoyqpB7RFHux4Akb2mhcRIibrJE1FpNiIGkn65QM+GjoQo+DRGOoHH2/8 FuB/+04P/hvAoC7Q7mg/nHh8g0V04EGcuKRpY41JZ4w6hxucJOeT/ERmgmhJ+FIJNfg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794582953; h=DMARC-Filter:Received:Received:DKIM-Signature:Date:From:To:Cc: Subject:Message-ID:References:MIME-Version:Content-Type: Content-Disposition:In-Reply-To; bh=V1YWPttXEi6HW26RX2hE76PCKuzOoDlXU7K4UAZ3+NM=; b=Qc5zfa6Zx7sMOodbZh9vabwQiljTnKXe0N61xazvUaH8jGpxQzvcFpSyB5mpMnQxxMkO IzukYgJ6SODaRTRdBnH8OdOxqqR42kmAJsexuRf1icJrHwwA+FkMnKqHWgducSx7Krkmb 6QmQEEjrJ1Q9H7n/glIom9UHNmlfV9Yyik1/AF/Lgx+DpX5La/TXa+IhyHN53mpirRCmh ev5Pj/QZhRdhtHvv/nBBSAN621o6um93WC6nLBoJ5HsbFpm6LK8SYpsKFyUZAFriKyFjV QIPDIGX6v/3TJkMD1d762zWSmAGvwVnUdVInX4tGHaTTjTELWbsygGCICo6j6f+BMgg== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=arm.com; spf=pass smtp.mailfrom=arm.com; dkim=pass header.d=arm.com header.i=@arm.com header.a=rsa-sha256 header.s=foss header.b=qXQmrCKd; arc=none smtp.remote-ip=217.140.110.172 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id E63F1606A339; Fri, 13 Nov 2026 15:15:52 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org E63F1606A339 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.a=rsa-sha256 header.s=foss header.b=qXQmrCKd Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 3EF42339; Fri, 13 Nov 2026 07:15:49 -0800 (PST) Received: from localhost (unknown [10.2.196.114]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id CFC833F85F; Fri, 13 Nov 2026 07:15:51 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1794582952; bh=8/RunaI4RGgcBAEHTWjUlS5O+ROOwppaIYc4rMMVIgQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=qXQmrCKdi1XXeajyZbt39aciqGvxmgxylKAOnZn9jFgyQyQT0v3dVwUbv043MzOew ZkQ3ZE4Lyo37EbONSQS25IILhW1hwvz2fcMG4WRg4ebIDlK7rDaERQ++wlT1sdV/R3 XHgX7CusAxNk7G8oJIaQ+uGx9pbcs0ualP1x0W3U= Date: Fri, 13 Nov 2026 15:15:49 +0000 From: Leo Yan To: Arnaldo Carvalho de Melo Cc: Namhyung Kim , Ingo Molnar , Thomas Gleixner , James Clark , Jiri Olsa , Ian Rogers , Adrian Hunter , Clark Williams , linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, Arnaldo Carvalho de Melo , Mike Leach , Robert Walker , Suzuki K Poulose , coresight@lists.linaro.org, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH v1 09/12] perf cs-etm: Fall back to the recorded instruction size on a failed read Message-ID: <20261113151549.GR9176@e132581.arm.com> References: <20261113150555.1163049-1-acme@kernel.org> <20261113150555.1163049-10-acme@kernel.org> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20261113150555.1163049-10-acme@kernel.org> Hi Arnaldo, On Fri, Nov 13, 2026 at 12:05:50PM -0300, Arnaldo Carvalho de Melo wrote: > From: Arnaldo Carvalho de Melo > > cs_etm__t32_instr_size() reads the instruction bytes from the traced > program's memory to tell a 16-bit from a 32-bit T32 instruction, but it > ignores cs_etm__frontend_mem_access() failing, which happens when the > DSO or its debug data is missing, and then reads the uninitialized > buffer. GCC 16 warns about it and build-test fails with -Werror. > > Use the instruction size recorded by the decoder, as the A32/A64 path > already does, when the read doesn't return the full two bytes. This patch is duplicate with: https://lore.kernel.org/linux-perf-users/20261113-perf_fix_gcc15_failure-v1-0-eae592c5ff64@arm.com/T/#m5f610e381705bc587a9ce3d31be4e1e0ed595506 I prefer that one, it handle cs_etm__frontend_mem_access() failure throughly.