From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 03710C433EF for ; Fri, 25 Mar 2022 19:27:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229546AbiCYT3O (ORCPT ); Fri, 25 Mar 2022 15:29:14 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58500 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229773AbiCYT2e (ORCPT ); Fri, 25 Mar 2022 15:28:34 -0400 Received: from mail.efficios.com (mail.efficios.com [167.114.26.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 472521EC9B7; Fri, 25 Mar 2022 12:02:33 -0700 (PDT) Received: from localhost (localhost [127.0.0.1]) by mail.efficios.com (Postfix) with ESMTP id A00793F928D; Fri, 25 Mar 2022 14:37:33 -0400 (EDT) Received: from mail.efficios.com ([127.0.0.1]) by localhost (mail03.efficios.com [127.0.0.1]) (amavisd-new, port 10032) with ESMTP id o23C3DmGDikb; Fri, 25 Mar 2022 14:37:33 -0400 (EDT) Received: from localhost (localhost [127.0.0.1]) by mail.efficios.com (Postfix) with ESMTP id 1AAED3F928C; Fri, 25 Mar 2022 14:37:33 -0400 (EDT) DKIM-Filter: OpenDKIM Filter v2.10.3 mail.efficios.com 1AAED3F928C DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=efficios.com; s=default; t=1648233453; bh=mwGMi7DQv+rIpXzPKYAh0aILg4rx7+9wE3psHKG8Ox8=; h=Date:From:To:Message-ID:MIME-Version; b=FFq8Id9RI4B+MAqAqNdDDT49nMdWQGHbMV0Vh81Wg8rKc9vZ6RZeZRvU25frcTrlI IyZmFRltt6UDeUjQzOL3MQYFy+oMO2AUv/LZQgMcQ2sQf+WaACwOW+EEA0t53znUPJ OQKikP7noZV+XcsnJ0YD27DpE5H+Bgx+lFohmuGJwsHiHXfCTaqUYrAS8ZFzRdO83J 4WTXE0UBk5xoZX3QREMglFPX0FmwYEA2ov/H6fLRx3Y8p1xLr+CcaM1aOSl59yGIQu FJxS1qNl0VG9p4EoelXanXI2mIrp8AdNGKa1JIBYXR2VQsoOWNS2LujOnHu+WgdVYd JDtdtWtGzDu9A== X-Virus-Scanned: amavisd-new at efficios.com Received: from mail.efficios.com ([127.0.0.1]) by localhost (mail03.efficios.com [127.0.0.1]) (amavisd-new, port 10026) with ESMTP id Rmp3GDtL7f2D; Fri, 25 Mar 2022 14:37:33 -0400 (EDT) Received: from mail03.efficios.com (mail03.efficios.com [167.114.26.124]) by mail.efficios.com (Postfix) with ESMTP id 0CDB93F8FCC; Fri, 25 Mar 2022 14:37:33 -0400 (EDT) Date: Fri, 25 Mar 2022 14:37:32 -0400 (EDT) From: Mathieu Desnoyers To: lttng-dev@lists.lttng.org, diamon-discuss@lists.linuxfoundation.org, linux-trace-users@vger.kernel.org, linux-kernel Message-ID: <1722467374.194740.1648233452935.JavaMail.zimbra@efficios.com> Subject: [RELEASE] LTTng-modules 2.13.3 and 2.12.8 (Linux kernel tracer) MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-Originating-IP: [167.114.26.124] X-Mailer: Zimbra 8.8.15_GA_4203 (ZimbraWebClient - FF98 (Linux)/8.8.15_GA_4232) Thread-Index: FdzCaxNCbhjFfBx2k4zpzfddPUUTBg== Thread-Topic: LTTng-modules 2.13.3 and 2.12.8 (Linux kernel tracer) Precedence: bulk List-ID: X-Mailing-List: linux-trace-users@vger.kernel.org Hi, This is a stable release announcement for the LTTng kernel tracer for the stable 2.12 and 2.13 branches. The releases are respectively 2.12.8 and 2.13.3. In the 2.13.3 release, two fixes are worth mentioning: * Fix: lttng ABI: lttng_counter_ioctl() tainted scalar The counter aggregate, clear and read functions (used for error reporting of the event notification feature) use a userspace-controlled "number_dimensions" argument as loop boundary. This ABI is only accessible from the root user, which limits the practical impact of this bug. * Fix: sample discarded events count before reserve Sampling the discarded events count in the buffer_end callback is done out of order, and may therefore include increments performed by following events (in following packets) if the thread doing the end-of-packet event write is interrupted for a long time. Sampling the event discarded counts before reserving space for the last event in a packet, and keeping this as part of the private ring buffer context, should fix this race. In lttng-modules, this scenario would only happen if an interrupt handler produces many events, when nested over an event between its reserve and commit. Note that if lttng-modules supports faultable tracepoints in the future, this may become more easy to trigger due to preemption. This fix is only part of the 2.13 stable branch and not backported to 2.12 because the lib ring buffer code used to implement this fix did not exist in 2.12. Given that the impact of this bug is only imprecision of discarded event reporting in corner-case scenarios (small impact, rare occurrence), the complexity of implementing this fix in 2.12 is not justified. The effect of this issue is that the lttng-tools tests/regression/tools/streaming/test_high_throughput_limits test is flaky. In the 2.12.8 release, a series of commits introduce support for the 5.17 Linux kernel. The 2.13 stable branch already supported that kernel in the prior releases. Feedback is welcome! Thanks, Mathieu Project website: https://lttng.org Documentation: https://lttng.org/docs Download link: https://lttng.org/download -- Mathieu Desnoyers EfficiOS Inc. http://www.efficios.com