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 B1EF0C2BA19 for ; Tue, 14 Apr 2020 12:06:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8DDF92075E for ; Tue, 14 Apr 2020 12:06:20 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="QOFlOi3S" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2439856AbgDNMGT (ORCPT ); Tue, 14 Apr 2020 08:06:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44280 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S2439854AbgDNMGR (ORCPT ); Tue, 14 Apr 2020 08:06:17 -0400 Received: from mail-pj1-x1032.google.com (mail-pj1-x1032.google.com [IPv6:2607:f8b0:4864:20::1032]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 71BADC061A0C for ; Tue, 14 Apr 2020 05:06:17 -0700 (PDT) Received: by mail-pj1-x1032.google.com with SMTP id o1so4268566pjs.4 for ; Tue, 14 Apr 2020 05:06:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:mime-version:content-disposition; bh=jm9THyL6NHvjyPBi15ToGJy65zugr7H20iHk/cdSJyw=; b=QOFlOi3SiyJSh29CrjLg5rBh9w6ZZ8aaSi7B/OPkpXhnURNFu5Kae07vhrLYCPeNX4 rakAqMmK1pT5rQk27k9914npkYLPEsrm2P9q9Q5E7K3nYw+0R2eRx5TotHZvCyQKMPhR jrTrCvky33YGF79+cgvWRq+DFLhgc3vKe085It7fdOnghG6Q6jP35YA7IwY02l9ZsPYz S4GL69rr6LeX56le+7rHlVJC8smv17hKJfuHkhkRczV1Tf9R9qHOuQW9Pl3mDWLFntYT GBuRT35WGP0+7Wvl+v7+E8B6ZdCTRtVaDw9xS/pkB+QFUwXhUFz20EIVRy3Anp581XFr Zi6Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:mime-version :content-disposition; bh=jm9THyL6NHvjyPBi15ToGJy65zugr7H20iHk/cdSJyw=; b=A7XPBfbW2bqeTlqoI8geKENhf0GeeXlrjJPH+CALGOi3gckkjB05TYpb0H3ZIIZJbo 0DHq4eh9yHsTzIARdyx46E/OpylLqlIULIMxEgiRKKv47um/9xVeZdfm8roq7PCATDSp OJSWWbaH8dJRVFI48lhM4stDWXC5CoEomMKIJ6xRF933DL1X4rt37LMzl4xU4TNo4CJF bNT8ocgFcnpq/1TntI+6vs0DTemzqBiyDq8G8qPi80L8hPywmHDSN09Ab/paRciIluZT JCiTKXKFo9mnexsydUVJwXXe9OKwBTeTpOu0daZJA/9Lk0X2/8hh5EAy1IaikxelQcPE /2TA== X-Gm-Message-State: AGi0PuZAoaCRaczHUMemHszoeaSXajXp83AFeWDiOimrtuN0DiOSbiR+ gOqgUo8P02kkFYGfm/agSxFHGlhO X-Google-Smtp-Source: APiQypJRXn/97TRn2MNg1Waw6AFG43jLHeMxlRcf0qV1QSSegyU9hzxzBnlJTEg+bSZdLe8Ro8YK5Q== X-Received: by 2002:a17:90b:3851:: with SMTP id nl17mr27295147pjb.59.1586865976472; Tue, 14 Apr 2020 05:06:16 -0700 (PDT) Received: from localhost ([2401:fa00:8f:203:5bbb:c872:f2b1:f53b]) by smtp.gmail.com with ESMTPSA id c10sm7991912pfc.23.2020.04.14.05.06.15 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 14 Apr 2020 05:06:15 -0700 (PDT) Date: Tue, 14 Apr 2020 21:06:13 +0900 From: Sergey Senozhatsky To: stable@vger.kernel.org Cc: Petr Mladek Subject: printk: queue wake_up_klogd irq_work only if per-CPU areas are ready Message-ID: <20200414120613.GD12779@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org Hello, Commit ab6f762f0f53162d41 Linus' HEAD. printk_deferred() does not make sure that it's safe to write to per-CPU data, which causes problems when printk_deferred() is invoked "too early", before per-CPU areas are initialized. There are multiple bug reports, e.g. https://bugzilla.kernel.org/show_bug.cgi?id=206847 -ss