From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ed1-x52e.google.com (mail-ed1-x52e.google.com [IPv6:2a00:1450:4864:20::52e]) by sourceware.org (Postfix) with ESMTPS id C53F43858D1E for ; Mon, 4 Apr 2022 11:21:42 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org C53F43858D1E Received: by mail-ed1-x52e.google.com with SMTP id w18so4386733edi.13 for ; Mon, 04 Apr 2022 04:21:42 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=UBXb/+gJNxGY7Fe5khZE543yva9RFfpTi4G3TDzCKE8=; b=hZn5+K3A8XmXkEs4+sbolxG+m2OY7en3vnI4iyJ1mSc/QrT6U3RG555ZfYTbV6s5Q0 5kZsDedjg9JhoIjoN35dwohLo3j+dhFfPS4khyckku0e/Frbhl0hb+FEE3hGuDknxrhK B24pfSeYh1ZhI2h3gXUU7W0m0wXKmjCrAaJkUAyUA66q+02oSi5CwAVOyC8tHBesIHhz Gq0sZAHKcWOW5rfshrFC4M+G65B3Q83BD7dhBo3BbwJz5LBR1AFhLtC2hawaCVaZFM0L eiIXbUAOQHWvDKPO4U/fdsfgUZXTqI40+dZgou1Hhhi/FzRoHcUcZtYpGXw8lv1DTkD7 2sYw== X-Gm-Message-State: AOAM531DKq2Phtg5o+tEw9eE3/daayEQma93DP2CvtR+LlQlrY5Xyyzk bEeEde8AjgiJvUp4QPAQSZbH8oU4c7ZtCdT3u6FOd9owsP7U6OVg X-Google-Smtp-Source: ABdhPJw9qyFtse3DjUDhkd6rp+FM7EWUWZ37EY9UCOPh1Qj4XCCYIxuxQg2y4kyi3RT25s+0Z2Z9DCmpB7zHvKrhMrk= X-Received: by 2002:a05:6402:5111:b0:419:74a6:6dc0 with SMTP id m17-20020a056402511100b0041974a66dc0mr32628907edd.293.1649071301628; Mon, 04 Apr 2022 04:21:41 -0700 (PDT) MIME-Version: 1.0 References: <6a4c5961-df38-40d6-9491-1f5a587a3dbf@www.fastmail.com> <9adcadfd-e6ba-4c0b-8e64-892ec7173bac@www.fastmail.com> In-Reply-To: <9adcadfd-e6ba-4c0b-8e64-892ec7173bac@www.fastmail.com> From: Daire Byrne Date: Mon, 4 Apr 2022 12:21:05 +0100 Message-ID: Subject: Re: newer kernel+systemtap & nfs.fop.open To: Serhei Makarov Cc: systemtap Content-Type: text/plain; charset="UTF-8" X-Spam-Status: No, score=-1.1 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, RCVD_IN_DNSWL_NONE, SPF_HELO_NONE, SPF_PASS, TXREP, T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.4 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on server2.sourceware.org X-BeenThere: systemtap@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Systemtap mailing list List-Unsubscribe: , List-Archive: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 04 Apr 2022 11:21:44 -0000 Serhei/David, Thanks for the suggestions and explanation. I get the same result with "fullpath_struct_file(task_current(), $filp)" using the v5.16 kernel and systemtap 4.7pre. As Serhei said, it seems like the mnt_parent is completely missing. But then I realised I had completely forgotten that I manually patched systemtap according to this just so I could get my script to compile at all: https://sourceware.org/bugzilla/show_bug.cgi?id=26184#c5 And now it also looks like a recent commit has been made to fix that particular issue so I'll try to pull the latest systemtap and try again. https://sourceware.org/git/?p=systemtap.git;a=commit;h=3739d47c4cc427ce4818d884f429a3efa85c38ae Daire On Fri, 1 Apr 2022 at 21:13, Serhei Makarov wrote: > > > > On Fri, Apr 1, 2022, at 10:55 AM, Serhei Makarov wrote: > > In this case the last commit > > to tapsets/linux/dentry.stp was in 2020 > > so it looks like we may have some catching up to the kernel > > to do. I'll investigate more (i.e. delve into kernel git history) > > and get back to you. > I'm got a 'read fault' running your example on Fedora 5.15.4-201.fc35.x86_64, > which indicates even further divergence later on. > Which kernel version were you running the example on? > > Looks like "struct mount" no longer defines the "mnt_parent" member > used by task_dentry_path() tapset function in /usr/share/systemtap/tapset/linux/dentry.stp > which is strange as the upstream Linux kernel code still uses that member > in the equivalent fs/d_path.c __prepend_path code. > > sutap -ve 'probe begin { if (@type_member_defined("mount", mnt_parent)) { print("foo") } else { print("bar") } exit() }' > > Very strange, as even checking the debugsource doesn't show any downstream changes > as found by > > $ debuginfod-find source /boot/vmlinuz-5.15.4-201.fc35.x86_64 /usr/src/debug/kernel-5.15.4/linux-5.15.4-201.fc35.x86_64/fs/d_path.c > > I'm also confused and will continue investigating until I become unconfused.