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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 AFF04C43334 for ; Tue, 4 Sep 2018 06:30:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5426620869 for ; Tue, 4 Sep 2018 06:30:58 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5426620869 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727498AbeIDKyg (ORCPT ); Tue, 4 Sep 2018 06:54:36 -0400 Received: from mail-wm0-f66.google.com ([74.125.82.66]:39897 "EHLO mail-wm0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726011AbeIDKyf (ORCPT ); Tue, 4 Sep 2018 06:54:35 -0400 Received: by mail-wm0-f66.google.com with SMTP id q8-v6so3017187wmq.4; Mon, 03 Sep 2018 23:30:53 -0700 (PDT) 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:openpgp:autocrypt :message-id:date:user-agent:mime-version:in-reply-to :content-language:content-transfer-encoding; bh=ST98tTJ1vfKmBeHShsV9vfwlwt2lYmIcYi9yFeCp9H4=; b=bcR50NVnw/hQLDRsWFN/Rf0WFfbG5Re/askksX+cDmSYhs8oqRd3GeMapEV9RyZ3lr zHJOsWvrLuoGDdFB5eb/MByB1ppms0Y6+RFPYshZtXRkm8UQO3Htdn/ukmzlAlNR/+yd +vvvAXLB588uEIgQ1gWzt435rFL40H3VogpMiYjhH3RdWHbbXoh/LSJG8Fn/VChlP7Vf r4eXYHELJrUtSlNNhWgxdJA77RrMDLMb8wYUFhB+PCtGxWpzrhSu7LXCey8GbHNfbMEU l7zRrlXrD34Y7BRBbtCqxnr+SjU4wRZWT2NhwWDOaJVRAGQNa1bwgV8ipzge/THwN6nV O9aA== X-Gm-Message-State: APzg51CofJe0zg2S5gKAUPi4sIA7HdHT36bSGYeay03JJ4qobQUGInGt d5FlsPznInuUO5Mo1R4wjvhzhpnG X-Google-Smtp-Source: ANB0VdYaQ0qqiPJTGmggTKBh0awzmnWgyo1aauYcgIAW2IgW4qVThhLZFk8GsVp2HKzANiqVhgMerA== X-Received: by 2002:a1c:908b:: with SMTP id s133-v6mr1664934wmd.69.1536042652819; Mon, 03 Sep 2018 23:30:52 -0700 (PDT) Received: from ?IPv6:2a01:4240:2e27:ad85:aaaa::70f? ([2a01:4240:2e27:ad85:aaaa::70f]) by smtp.gmail.com with ESMTPSA id o15-v6sm17610338wru.23.2018.09.03.23.30.51 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 03 Sep 2018 23:30:52 -0700 (PDT) Subject: Re: [PATCHv2 2/4] tty: Hold tty_ldisc_lock() during tty_reopen() To: Sergey Senozhatsky , Dmitry Safonov Cc: linux-kernel@vger.kernel.org, Dmitry Safonov <0x7f454c46@gmail.com>, Daniel Axtens , Dmitry Vyukov , Michael Neuling , Mikulas Patocka , Nathan March , =?UTF-8?B?UGFzaSBLw6Rya2vDpGluZW4=?= , Peter Hurley , Tan Xiaojun , Tetsuo Handa , syzbot+3aa9784721dfb90e984d@syzkaller.appspotmail.com, Greg Kroah-Hartman , stable@vger.kernel.org References: <20180903165257.29227-1-dima@arista.com> <20180903165257.29227-3-dima@arista.com> <20180904015139.GA4251@jagdpanzerIV> From: Jiri Slaby Openpgp: preference=signencrypt Autocrypt: addr=jslaby@suse.com; prefer-encrypt=mutual; keydata= xsFNBE6S54YBEACzzjLwDUbU5elY4GTg/NdotjA0jyyJtYI86wdKraekbNE0bC4zV+ryvH4j rrcDwGs6tFVrAHvdHeIdI07s1iIx5R/ndcHwt4fvI8CL5PzPmn5J+h0WERR5rFprRh6axhOk rSD5CwQl19fm4AJCS6A9GJtOoiLpWn2/IbogPc71jQVrupZYYx51rAaHZ0D2KYK/uhfc6neJ i0WqPlbtIlIrpvWxckucNu6ZwXjFY0f3qIRg3Vqh5QxPkojGsq9tXVFVLEkSVz6FoqCHrUTx wr+aw6qqQVgvT/McQtsI0S66uIkQjzPUrgAEtWUv76rM4ekqL9stHyvTGw0Fjsualwb0Gwdx ReTZzMgheAyoy/umIOKrSEpWouVoBt5FFSZUyjuDdlPPYyPav+hpI6ggmCTld3u2hyiHji2H cDpcLM2LMhlHBipu80s9anNeZhCANDhbC5E+NZmuwgzHBcan8WC7xsPXPaiZSIm7TKaVoOcL 9tE5aN3jQmIlrT7ZUX52Ff/hSdx/JKDP3YMNtt4B0cH6ejIjtqTd+Ge8sSttsnNM0CQUkXps w98jwz+Lxw/bKMr3NSnnFpUZaxwji3BC9vYyxKMAwNelBCHEgS/OAa3EJoTfuYOK6wT6nadm YqYjwYbZE5V/SwzMbpWu7Jwlvuwyfo5mh7w5iMfnZE+vHFwp/wARAQABzSBKaXJpIFNsYWJ5 IDxqaXJpc2xhYnlAZ21haWwuY29tPsLBewQTAQIAJQIbAwYLCQgHAwIGFQgCCQoLBBYCAwEC HgECF4AFAk6S6P4CGQEACgkQvSWxBAa0cEl1Sg//UMXp//d4lP57onXMC2y8gafT1ap/xuss IvXR+3jSdJCHRaUFTPY2hN0ahCAyBQq8puUa6zaXco5jIzsVjLGVfO/s9qmvBTKw9aP6eTU7 77RLssLlQYhRzh7vapRRp4xDBLvBGBv9uvWORx6dtRjh+e0J0nKKce8VEY+jiXv1NipWf+RV vg1gVbAjBnT+5RbJYtIDhogyuBFg14ECKgvy1Do6tg9Hr/kU4ta6ZBEUTh18Io7f0vr1Mlh4 yl2ytuUNymUlkA/ExBNtOhOJq/B087SmGwSLmCRoo5VcRIYK29dLeX6BzDnmBG+mRE63IrKD kf/ZCIwZ7cSbZaGo+gqoEpIqu5spIe3n3JLZQGnF45MR+TfdAUxNQ4F1TrjWyg5Fo30blYYU z6+5tQbaDoBbcSEV9bDt6UOhCx033TrdToMLpee6bUAKehsUctBlfYXZP2huZ5gJxjINRnlI gKTATBAXF+7vMhgyZ9h7eARG6LOdVRwhIFUMGbRCCMXrLLnQf6oAHyVnsZU1+JWANGFBjsyy fRP2+d8TrlhzN9FoIGYiKjATR9CpJZoELFuKLfKOBsc7DfEBpsdusLT0vlzR6JaGae78Od5+ ljzt88OGNyjCRIb6Vso0IqEavtGOcYG8R5gPhMV9n9/bCIVqM5KWJf/4mRaySZp7kcHyJSb0 O6nOwU0ETpLnhgEQAM+cDWLL+Wvc9cLhA2OXZ/gMmu7NbYKjfth1UyOuBd5emIO+d4RfFM02 XFTIt4MxwhAryhsKQQcA4iQNldkbyeviYrPKWjLTjRXT5cD2lpWzr+Jx7mX7InV5JOz1Qq+P +nJWYIBjUKhI03ux89p58CYil24Zpyn2F5cX7U+inY8lJIBwLPBnc9Z0An/DVnUOD+0wIcYV nZAKDiIXODkGqTg3fhZwbbi+KAhtHPFM2fGw2VTUf62IHzV+eBSnamzPOBc1XsJYKRo3FHNe LuS8f4wUe7bWb9O66PPFK/RkeqNX6akkFBf9VfrZ1rTEKAyJ2uqf1EI1olYnENk4+00IBa+B avGQ8UW9dGW3nbPrfuOV5UUvbnsSQwj67pSdrBQqilr5N/5H9z7VCDQ0dhuJNtvDSlTf2iUF Bqgk3smln31PUYiVPrMP0V4ja0i9qtO/TB01rTfTyXTRtqz53qO5dGsYiliJO5aUmh8swVpo tgK4/57h3zGsaXO9PGgnnAdqeKVITaFTLY1ISg+Ptb4KoliiOjrBMmQUSJVtkUXMrCMCeuPD GHo739Xc75lcHlGuM3yEB//htKjyprbLeLf1y4xPyTeeF5zg/0ztRZNKZicgEmxyUNBHHnBK HQxz1j+mzH0HjZZtXjGu2KLJ18G07q0fpz2ZPk2D53Ww39VNI/J9ABEBAAHCwV8EGAECAAkF Ak6S54YCGwwACgkQvSWxBAa0cEk3tRAAgO+DFpbyIa4RlnfpcW17AfnpZi9VR5+zr496n2jH /1ldwRO/S+QNSA8qdABqMb9WI4BNaoANgcg0AS429Mq0taaWKkAjkkGAT7mD1Q5PiLr06Y/+ Kzdr90eUVneqM2TUQQbK+Kh7JwmGVrRGNqQrDk+gRNvKnGwFNeTkTKtJ0P8jYd7P1gZb9Fwj 9YLxjhn/sVIhNmEBLBoI7PL+9fbILqJPHgAwW35rpnq4f/EYTykbk1sa13Tav6btJ+4QOgbc ezWIwZ5w/JVfEJW9JXp3BFAVzRQ5nVrrLDAJZ8Y5ioWcm99JtSIIxXxt9FJaGc1Bgsi5K/+d yTKLwLMJgiBzbVx8G+fCJJ9YtlNOPWhbKPlrQ8+AY52Aagi9WNhe6XfJdh5g6ptiOILm330m kR4gW6nEgZVyIyTq3ekOuruftWL99qpP5zi+eNrMmLRQx9iecDNgFr342R9bTDlb1TLuRb+/ tJ98f/bIWIr0cqQmqQ33FgRhrG1+Xml6UXyJ2jExmlO8JljuOGeXYh6ZkIEyzqzffzBLXZCu jlYQDFXpyMNVJ2ZwPmX2mWEoYuaBU0JN7wM+/zWgOf2zRwhEuD3A2cO2PxoiIfyUEfB9SSmf faK/S4xXoB6wvGENZ85Hg37C7WDNdaAt6Xh2uQIly5grkgvWppkNy4ZHxE+jeNsU7tg= Message-ID: <7e62b122-3b9e-dc46-d99f-9055bb67d670@suse.com> Date: Tue, 4 Sep 2018 08:30:50 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <20180904015139.GA4251@jagdpanzerIV> Content-Type: text/plain; charset=iso-8859-2 Content-Language: en-GB Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 09/04/2018, 03:51 AM, Sergey Senozhatsky wrote: > On (09/03/18 17:52), Dmitry Safonov wrote: >> >> We've seen the following crash on v4.9.108 stable: >> >> BUG: unable to handle kernel paging request at 0000000000002260 >> IP: [..] n_tty_receive_buf_common+0x5f/0x86d >> Workqueue: events_unbound flush_to_ldisc >> Call Trace: >> [..] n_tty_receive_buf2 >> [..] tty_ldisc_receive_buf >> [..] flush_to_ldisc >> [..] process_one_work >> [..] worker_thread >> [..] kthread >> [..] ret_from_fork >> >> tty_ldisc_reinit() should be called with ldisc_sem hold for writing, >> which will protect any reader against line discipline changes. >> >> Cc: Greg Kroah-Hartman >> Cc: Jiri Slaby >> Cc: stable@vger.kernel.org # depends on commit b027e2298bd5 ("tty: fix >> data race between tty_init_dev and flush of buf") > > I believe there's a "Fixes" tag for that > > Fixes: b027e2298bd5 ("tty: fix data race between tty_init_dev and flush of buf") > Cc: stable@vger.kernel.org Nope, it would be translated as: Backport-first: b027e2298bd5 :) thanks, -- js suse labs