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 X-Spam-Level: X-Spam-Status: No, score=-0.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 74C8CC433DF for ; Wed, 17 Jun 2020 10:30:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 530AF208B3 for ; Wed, 17 Jun 2020 10:30:54 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="C1Rqzc/j" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725967AbgFQKax (ORCPT ); Wed, 17 Jun 2020 06:30:53 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50280 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725901AbgFQKaw (ORCPT ); Wed, 17 Jun 2020 06:30:52 -0400 Received: from mail-wr1-x42a.google.com (mail-wr1-x42a.google.com [IPv6:2a00:1450:4864:20::42a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 41236C061573; Wed, 17 Jun 2020 03:30:52 -0700 (PDT) Received: by mail-wr1-x42a.google.com with SMTP id r7so1781559wro.1; Wed, 17 Jun 2020 03:30:51 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:from:date:message-id:subject:to:cc; bh=6cV4DHswB2EyeE07H4W7XCwzmJOtlP+W1W6yT4bg52g=; b=C1Rqzc/japPum67ZTnuAVaiq2NPpCxTUZk2OOs7u92om/UHf8Ai1fJSa95yb+EikCj FBZ1VOx2o/jL0/ss9n2sPgAJHTd3graTtuDv9BYwoKAb93VfJjObyyHcoutjcoGT8EOC 9hPIZjJSMZUyWOzmqJYxnHFdApHcEoxQYfIJd6h3fmQqZNcRqTmQ+WqPLNWgbLW0Q86p TG4UxOrr2COtSPwxiPlsjpDusl8PVaBkUjxdYp+H9OkjEmKCu7Lq1Y+6hFmqe+Epn+Ht wYEVI9ippMMUZlfY+0xSNPJ4TMZ0Cvy7Ac3jJJYc2Hs7T2I8mQ1tafjsm7vtC6fpfdal t0tA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:from:date:message-id:subject:to:cc; bh=6cV4DHswB2EyeE07H4W7XCwzmJOtlP+W1W6yT4bg52g=; b=XrmTVsgOpuLl1sxOPDvj6VkVWK4erBCWejzLLpcAbfj5UTmxjG0HFlLtN6r3jtareE qVTyrkrccj3H9Eym+ogjaDvLsT4VYwyU0bwuMZX6Pafi+fVJ4Q8Uo1CquvVUzdpwf8vu aFjejUMaqT/2amn67u5gor/3HE5bkRNatXssO7nyr20ngJqE9LopjQggX2R48CR8hGVi Y8mB77tfuTiaJFiaeMi69YImPVIZb3T6ypc1er19NZwc4ETs+Hwiir2YcZtoJvSapUo/ gM0GdDpVqmeGv+V0sSo6qeekUCNxsrKwc2UCUTphKaMXn+B6K4s5Ntpwh2LMjWzNG3rj Tz2Q== X-Gm-Message-State: AOAM530LtSkN8Iw3JvayCp0EXao6kmNKV2oFewer6GLvrPUSwLNOb1Eu F97S0VaDKR2yU2R6BiA57FMofIrt5VW09//6Hxw= X-Google-Smtp-Source: ABdhPJyeQZRqJRgjSeusf9v5yBFBGvFjqIYCsu8BTeFkhrJ4QbR0F92kIGENOe/0gNpO5f5goNfGZYn7RWQvl6s5vns= X-Received: by 2002:adf:ecc8:: with SMTP id s8mr4518383wro.317.1592389850778; Wed, 17 Jun 2020 03:30:50 -0700 (PDT) MIME-Version: 1.0 From: Ming Lei Date: Wed, 17 Jun 2020 18:30:39 +0800 Message-ID: Subject: krobe: __blkdev_put probe is missed To: "Naveen N. Rao" , Anil S Keshavamurthy , Linux Kernel Mailing List , "David S. Miller" , Masami Hiramatsu Cc: Steven Rostedt , linux-block Content-Type: text/plain; charset="UTF-8" Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org Hello Guys, I found probe on __blkdev_put is missed, which can be observed via bcc/perf reliably: 1) start trace - perf probe __blkdev_put - perf trace -a -e probe:__blkdev_put or /usr/share/bcc/tools/stackcount __blkdev_put 2) run the following command: blockdev --getbsz /dev/sda1 3) 'perf trace' or stackcount just dumps one trace event, and it should have been two __blkdev_put() traces, since one __blkdev_put() is called for partition(/dev/sda1), and another is for disk(/dev/sda). If trace_printk() is added in __blkdev_put(), two events will be captured from ftrace. The only special thing about __blkdev_put() is that the function will call into itself. However, no such issue on __blkdev_get() which calls itself too. Thanks, Ming Lei