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=-2.1 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, USER_AGENT_SANE_1 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 AF229C54E49 for ; Sun, 10 May 2020 06:48:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 779552070B for ; Sun, 10 May 2020 06:48:35 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="byOnXGnf" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727789AbgEJGse (ORCPT ); Sun, 10 May 2020 02:48:34 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56060 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1725810AbgEJGsd (ORCPT ); Sun, 10 May 2020 02:48:33 -0400 Received: from mail-pj1-x1042.google.com (mail-pj1-x1042.google.com [IPv6:2607:f8b0:4864:20::1042]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C6229C061A0C; Sat, 9 May 2020 23:48:33 -0700 (PDT) Received: by mail-pj1-x1042.google.com with SMTP id t40so6189228pjb.3; Sat, 09 May 2020 23:48:33 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=l/8M9WGtxo6PbsxhSHfbtuvDOM6UKdX+q+/zdI2w/Dw=; b=byOnXGnfKoI8tIQG9NZ1UOLtVgbChvyiBOYc7BuDW9t/w0KSM5B0xIDhb4Xza6PDM4 IlY9mNb6hRgNfEFDjDlVjS/LBS8vN0ubXNz1Ag1pylQJRewpBWTNF4nc4Ju8X76jcOUq a8s6iPFY4Hr1TDkCqr8ugUnsIhBQbW/8QKlvkjiC/RSwS7xKd8sG47OHxeNN4AEEOP3C XhYrElDJYeJZjYS1GSdqha+bCIN4crpYvabg5Aia0zZOoKonwh8jEAiHN50lWA5xmQKb kR6Sn2ov0OlLsS4WpCaJ25Q1cItsWyzQZOSx5W22mwAUE21kf58lweCzr5Ktg+/5m2uQ /itA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=l/8M9WGtxo6PbsxhSHfbtuvDOM6UKdX+q+/zdI2w/Dw=; b=XMPXrxGkR9Ir82VJYUxT8nSN9jUEPGUGhesPE0LwmObdo4a6+XWiHfro+WgnZqjiQL qIFA3tG81u1dVh+5r9AWdKSvaosifNstEtIE+xZL7BsB8/pfpaU0QRH7ZSPljXgsxV7X wi9Sh6FgCHSPSkVTdSGgkEq/tE6HdUtaYaeQh+rF3ZtY8y0FXF7a3QaD3FPjzK1xTxet XkaMOp9G3zSyx/pWyyWA9lCZoPHGTFkz+yrAj9cqCNMpRivOQPhCB6rxUWcqLjQ8Qs48 PHF7mNkul4QbYmc2UjnDrYunJ/JMJabG6Zb40TchuCZRvUSp0Y7W5OiE3eYrSucDxAGH BBnw== X-Gm-Message-State: AGi0PuaUbNkgdCV4LNyWX7NCGTYlhJ3YBEyPltvxVDxm4yHnXDMjKfZu WxzAZKiyyBRsNF5wWJCa1tDHLtk8 X-Google-Smtp-Source: APiQypJ+2JyRPcnqESYdW+4iYrPZYrPa/bZhrQndJw3KOcbNOSFFmTW93Nobsr6ie+4qZhB35QlpjQ== X-Received: by 2002:a17:90a:fb4e:: with SMTP id iq14mr15875216pjb.146.1589093312825; Sat, 09 May 2020 23:48:32 -0700 (PDT) Received: from ASMDT.1 ([114.125.231.97]) by smtp.gmail.com with ESMTPSA id z15sm6472198pjt.20.2020.05.09.23.48.26 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sat, 09 May 2020 23:48:32 -0700 (PDT) Subject: Re: USB Attached SCSI breakage due no udev involvement To: Greg KH Cc: oneukum@suse.com, linux-usb@vger.kernel.org, linux-scsi@vger.kernel.org, usb-storage@lists.one-eyed-alien.net, stern@rowland.harvard.edu, linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org, usb-storage@lists.one-eyed-alien.net, stern@rowland.harvard.edu, linux-kernel@vger.kernel.org References: <20200510054717.GA3365021@kroah.com> From: Dio Putra Message-ID: <1f9c0b30-f440-de43-366f-28ccba6a22e2@gmail.com> Date: Sun, 10 May 2020 13:48:24 +0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.8.0 MIME-Version: 1.0 In-Reply-To: <20200510054717.GA3365021@kroah.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 5/10/20 12:47 PM, Greg KH wrote: > On Sun, May 10, 2020 at 09:55:57AM +0700, Dio Putra wrote: >> Hi, it's first time for me to report user-space breakage in here, so >> i'm begging your pardon. >> >> I want to report that Linux 5.4 breaking my USB mount workflow due >> udevadm monitor report here (I'm using vanilla kernel 5.4.39 on >> Slackware64 Current and vanilla kernel 4.4.221 on Slackware64 14.2): > > > > Sorry, but what actually changed that you can see in the logs? Sorry, what do you mean? The dmesg log or the kernel changelogs? > > What functionality broke? What used to work that no longer does work? > Yes, it supposed that just work and kernel could talk with udev, not just handled by the kernel. Here's my personal conclusion: [Slackware64-Current linux-5.4.39]$ sudo strace -p 2417 strace: Process 2417 attached write(1, "KERNEL[672.150926] remove /dev"..., 84) = 84 epoll_wait(3, [{EPOLLIN, {u32=5, u64=5}}], 4, -1) = 1 recvmsg(5, {msg_name={sa_family=AF_NETLINK, nl_pid=0, nl_groups=0x000001}, msg_namelen=128->12, msg_iov=[{iov_base="remove@/devices/pci0000:00/0000:"..., iov_len=8192}], msg_iovlen=1, msg_control=[{cmsg_len=28, cmsg_level=SOL_SOCKET, cmsg_type=SCM_CREDENTIALS, cmsg_data={pid=0, uid=0, gid=0}}], msg_controllen=32, msg_flags=0}, 0) = 269 write(1, "KERNEL[672.151622] remove /dev"..., 122) = 122 epoll_wait(3, [{EPOLLIN, {u32=5, u64=5}}], 4, -1) = 1 recvmsg(5, {msg_name={sa_family=AF_NETLINK, nl_pid=0, nl_groups=0x000001}, msg_namelen=128->12, msg_iov=[{iov_base="remove@/devices/pci0000:00/0000:"..., iov_len=8192}], msg_iovlen=1, msg_control=[{cmsg_len=28, cmsg_level=SOL_SOCKET, cmsg_type=SCM_CREDENTIALS, cmsg_data={pid=0, uid=0, gid=0}}], msg_controllen=32, msg_flags=0}, 0) = 255 write(1, "KERNEL[672.152396] remove /dev"..., 138) = 138 epoll_wait(3, [{EPOLLIN, {u32=5, u64=5}}], 4, -1) = 1 recvmsg(5, {msg_name={sa_family=AF_NETLINK, nl_pid=0, nl_groups=0x000001}, msg_namelen=128->12, msg_iov=[{iov_base="remove@/devices/virtual/bdi/11:0"..., iov_len=8192}], msg_iovlen=1, msg_control=[{cmsg_len=28, cmsg_level=SOL_SOCKET, cmsg_type=SCM_CREDENTIALS, cmsg_data={pid=0, uid=0, gid=0}}], msg_controllen=32, msg_flags=0}, 0) = 107 write(1, "KERNEL[672.153191] remove /dev"..., 60) = 60 ...... "So the summary of syscall on linux-5.4.39 it's something like: write --> epoll_wait --> recvmsg (direct call from kernel only, no udev dependencies has been called ever) --> write" [Slackware64-14.2 linux-kernel-4.4.221] $ sudo strace -p 2102 strace: Process 2102 attached write(1, "KERNEL[160.475104] remove /dev"..., 84) = 84 epoll_wait(3, [{EPOLLIN, {u32=4, u64=4}}], 4, -1) = 1 recvmsg(4, {msg_name(12)={sa_family=AF_NETLINK, pid=598, groups=00000002}, msg_iov(1)=[{"libudev\0\376\355\312\376(\0\0\0(\0\0\0\375\0\0\0\5w\305\345\261\2Ge"..., 8192}], msg_controllen=32, [{cmsg_len=28, cmsg_level=SOL_SOCKET, cmsg_type=SCM_CREDENTIALS, {pid=2116, uid=0, gid=0}}], msg_flags=0}, 0) = 293 write(1, "UDEV [160.476746] remove /dev"..., 84) = 84 epoll_wait(3, [{EPOLLIN, {u32=5, u64=5}}], 4, -1) = 1 recvmsg(5, {msg_name(12)={sa_family=AF_NETLINK, pid=0, groups=00000001}, msg_iov(1)=[{"remove@/devices/pci0000:00/0000:"..., 8192}], msg_controllen=32, [{cmsg_len=28, cmsg_level=SOL_SOCKET, cmsg_type=SCM_CREDENTIALS, {pid=0, uid=0, gid=0}}], msg_flags=0}, 0) = 256 write(1, "KERNEL[160.478096] remove /dev"..., 76) = 76 epoll_wait(3, [{EPOLLIN, {u32=4, u64=4}}], 4, -1) = 1 recvmsg(4, {msg_name(12)={sa_family=AF_NETLINK, pid=598, groups=00000002}, msg_iov(1)=[{"libudev\0\376\355\312\376(\0\0\0(\0\0\0\26\2\0\0\5w\305\345'\370\365\f"..., 8192}], msg_controllen=32, [{cmsg_len=28, cmsg_level=SOL_SOCKET, cmsg_type=SCM_CREDENTIALS, {pid=2116, uid=0, gid=0}}], msg_flags=0}, 0) = 574 write(1, "UDEV [160.495353] remove /dev"..., 76) = 76 epoll_wait(3, [{EPOLLIN, {u32=5, u64=5}}], 4, -1) = 1 recvmsg(5, {msg_name(12)={sa_family=AF_NETLINK, pid=0, groups=00000001}, msg_iov(1)=[{"add@/devices/pci0000:00/0000:00:"..., 8192}], msg_controllen=32, [{cmsg_len=28, cmsg_level=SOL_SOCKET, cmsg_type=SCM_CREDENTIALS, {pid=0, uid=0, gid=0}}], msg_flags=0}, 0) = 250 write(1, "KERNEL[161.109310] add /dev"..., 76) = 76 ...... "So the summary of syscall on linux-4.4.221 it's something like: write --> epoll_wait --> recvmsg (libudev has been called) --> write (UDEV has been called) --> epoll_wait -> recvmsg (libudev has been called again)-> write" > And 4.4.221 is quite different from 5.4, is that the jump that you are > seeing breakage in, or is it in some smaller jump? > Yeah, I know it's really different between linux-4.4 and linux-5.4 > thanks, > > greg k-h >