From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5F79A606A337 for ; Fri, 13 Nov 2026 15:15:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.a=rsa-sha256 header.s=bombadil.20210309 header.b=4/iTk6fX; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.a=rsa-sha256 header.s=foss header.b=qXQmrCKd DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Unsubscribe-Post:List-Owner; bh=V1YWPttXEi6HW26RX2hE76PCKuzOoDlXU7K4UAZ3+NM=; b=4/iTk6fXgw4k8Eduj5oJsCa/6U FxbGV+iIlv95HF3kiE6eNWLGz9qY/RBifEaTGYWFyMrxso2TqO2awpcG0vIGRi4P7wdpVVhoYWc3I y9t4cf/sPlTz8MnVkQdMsB0mNmnRPysEqNRtFtiY+0jYJsNzLaDw+icg5pGVtezxtTjZGCndz4FI6 acNgwhdYg5zmquas1XAgnebjIsDz87sOS0oVvTWSTySJUdzuMiUY6g/6+6NppjSsnWUrfrZfFZu2U KDT2CqS9o/TaSWlEenE+PHdQsaV/uZAJzJ1y52b+mlKgVIv8iWG7plYpHMa4kYpW5UHj5UakHjq1b qsl0Jttw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.100.1 #2 (Red Hat Linux)) id 1xRt0O-0000000DMYh-10mC; Fri, 13 Nov 2026 15:15:56 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.100.1 #2 (Red Hat Linux)) id 1xRt0L-0000000DMXv-1imc for linux-arm-kernel@lists.infradead.org; Fri, 13 Nov 2026 15:15:55 +0000 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-Archived-By: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20261113150555.1163049-10-acme@kernel.org> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20261113_071553_491716_18607B06 X-CRM114-Status: GOOD ( 11.90 ) X-Spam-Score: -4.4 (----) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" X-Spam-Status: No, score=-5.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=no autolearn_force=no version=4.0.1 X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 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.