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=-3.3 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 30501C0044C for ; Thu, 1 Nov 2018 00:25:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C17DA20664 for ; Thu, 1 Nov 2018 00:24:59 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=arista.com header.i=@arista.com header.b="iaDZVPHt" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C17DA20664 Authentication-Results: mail.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=arista.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 S1726266AbeKAJZa (ORCPT ); Thu, 1 Nov 2018 05:25:30 -0400 Received: from mail-ed1-f68.google.com ([209.85.208.68]:44881 "EHLO mail-ed1-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725970AbeKAJZ3 (ORCPT ); Thu, 1 Nov 2018 05:25:29 -0400 Received: by mail-ed1-f68.google.com with SMTP id n19-v6so4213132edq.11 for ; Wed, 31 Oct 2018 17:24:55 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=arista.com; s=googlenew; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=AMG15DGucezO+5b7xza6DB5g0NQ7vbcTXol7ObZ389M=; b=iaDZVPHtx55/QS26V7+6Hm0VXueSzEldiK4I+RsTrlr+LVeB/JUJCHRIBXpWlmjOgy UQCVdxdMeDzwfrXRS5nW0PMU/cp7JfrtUwLtuaPNAyUSbByj145nJUyzf4gLW9wrFuIp jEIyxlexpGIaPCuYWUvfmqpNteYImuARjR40+KRMtZD/fcae8UOqYeimXkRs4Yc1Ghb1 bLYhgQa0OFs4AjsgEao+tRZQquSLciRjxFc4ZIYAx3/Ofi+AqPrpWlwb3UjKnfGvIGvu WaiFbqnAtB33u5lxRYtlNNXbrgwUuA1IQUL8aw6NSblpXOr+TaPQA78OqOa6ZZgTeujv aZUA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=AMG15DGucezO+5b7xza6DB5g0NQ7vbcTXol7ObZ389M=; b=tDw5aLZ7Ev5aUNexIrcqHIziebRULIOAmAcRwUpQ9HaW1fEHFXE7V3OaIfoG9x+rDv cV7fMW4CJ+ur9aVoEaK3Ru51k3ihU1S3cKsSeIbit4lbGNmbKJwQk1lwWcFomOmt4qXq aOnzsZnCYN/Uzo4VNV6svDoh4DuKXnrXlcIcOMDMFgc5bYShviquXu3ZEmY+UOfZzf/z IlZIOwTUL7yMzOhx8Onndl90nnPQU9z+hkzrBktUjHvicjwOfUKhhNRpzLO8r5Xv7Z7s rHhfilzpRxNZpnHO1TgKKVckS/2JxD2MIaMeJ2cUwCYCoVSpi9nnBWkAtJ+xw3LP+Re1 jdgA== X-Gm-Message-State: AGRZ1gLcqNufwgKaM4F5jRstpVz8MBjrZxYtbaLR1GqIrN/GdgPqAWdz k7aaQrhnb2RVSrueTzCBMjRwOk+0NqM= X-Google-Smtp-Source: AJdET5dAkU9WS4uvQRwcKbhH4e30BSi7IrtAkdRvgwMO7qfQIFi2xHSzl/0fHNQeqRaMNMKogOMlkA== X-Received: by 2002:aa7:da86:: with SMTP id q6-v6mr3865947eds.13.1541031894893; Wed, 31 Oct 2018 17:24:54 -0700 (PDT) Received: from Mindolluin.ire.aristanetworks.com ([217.173.96.166]) by smtp.gmail.com with ESMTPSA id s12-v6sm10188175edd.39.2018.10.31.17.24.53 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 31 Oct 2018 17:24:53 -0700 (PDT) From: Dmitry Safonov To: linux-kernel@vger.kernel.org Cc: Dmitry Safonov <0x7f454c46@gmail.com>, Dmitry Safonov , Daniel Axtens , Dmitry Vyukov , Mark Rutland , Michael Neuling , Mikulas Patocka , Nathan March , =?UTF-8?q?Pasi=20K=C3=A4rkk=C3=A4inen?= , Peter Hurley , Peter Zijlstra , "Rong, Chen" , Sergey Senozhatsky , Tan Xiaojun , Tetsuo Handa , Greg Kroah-Hartman , Jiri Slaby , stable@vger.kernel.org, Jiri Slaby , syzbot+3aa9784721dfb90e984d@syzkaller.appspotmail.com, Tetsuo Handa Subject: [PATCHv6 0/7] tty: Hold write ldisc sem in tty_reopen() Date: Thu, 1 Nov 2018 00:24:45 +0000 Message-Id: <20181101002452.5483-1-dima@arista.com> X-Mailer: git-send-email 2.19.1 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi all, Here are fixes that worth to have in the @stable, as they were hit by different people, including Arista on v4.9 stable. And for linux-next - adding lockdep asserts for line discipline changing code, verifying that write ldisc sem will be held forthwith. Mikulas, can you add your tested-by on this patches set again, please? I tried to reproduce reboot issue on qemu-hppa and even built cross-compiler for pa-risc.. but was unlucky in reproducing. Thanks, Dima Changes since v5: - Better commit tags - Hopefully fixed issue with reboot on pa-risc with Debian 5 Changes since v4: - back to lock ldisc with (5*HZ) timeout in tty_reopen() (LKP report link: lkml.kernel.org/r/<1536940609.3185.29.camel@arista.com>) - reordered 3/7 with 2/7 for LKP robot Changes since v3: - Added tested-by Mark Rutland (thanks!) - Dropped patch with smp_wmb() - wrong idea - lockdep_assert_held() should be actually lockdep_assert_held_exclusive() - Described why tty_ldisc_open() can be called without ldisc_sem held for pty slave end (o_tty). - Added Peter's patch for dropping self-made lockdep annotations - Fix for a reader(s) of ldisc semaphore waiting for an active reader(s) Changes since v2: - Added reviewed-by tags - Hopefully, fixed reported by 0-day issue. - Added optional fix for wait_readers decrement Changes since v1: - Added tested-by/reported-by tags - Dropped 3/4 (locking tty pair for lockdep sake), Because of that - not adding lockdep_assert_held() in tty_ldisc_open() - Added 4/4 cleanup to inc tty->count only on success of tty_ldisc_reinit() - lock ldisc without (5*HZ) timeout in tty_reopen() v1 link: lkml.kernel.org/r/<20180829022353.23568-1-dima@arista.com> v2 link: lkml.kernel.org/r/<20180903165257.29227-1-dima@arista.com> v3 link: lkml.kernel.org/r/<20180911014821.26286-1-dima@arista.com> v4 link: lkml.kernel.org/r/<20180912001702.18522-1-dima@arista.com> Cc: Daniel Axtens Cc: Dmitry Vyukov Cc: Mark Rutland Cc: Michael Neuling Cc: Mikulas Patocka Cc: Nathan March Cc: Pasi Kärkkäinen Cc: Peter Hurley Cc: Peter Zijlstra Cc: "Rong, Chen" Cc: Sergey Senozhatsky Cc: Tan Xiaojun Cc: Tetsuo Handa (please, ignore if I Cc'ed you mistakenly) Dmitry Safonov (6): tty/ldsem: Wake up readers after timed out down_write() tty: Hold tty_ldisc_lock() during tty_reopen() tty: Don't block on IO when ldisc change is pending tty: Simplify tty->count math in tty_reopen() tty/ldsem: Add lockdep asserts for ldisc_sem tty/ldsem: Decrement wait_readers on timeouted down_read() Peter Zijlstra (1): tty/ldsem: Convert to regular lockdep annotations drivers/tty/n_hdlc.c | 4 +-- drivers/tty/n_r3964.c | 2 +- drivers/tty/n_tty.c | 8 +++--- drivers/tty/tty_io.c | 14 ++++++---- drivers/tty/tty_ldisc.c | 16 +++++++++++ drivers/tty/tty_ldsem.c | 62 +++++++++++++++++------------------------ include/linux/tty.h | 7 +++++ 7 files changed, 63 insertions(+), 50 deletions(-) -- 2.19.1