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=-2.3 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, URIBL_BLOCKED,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 137EAC4CECE for ; Fri, 13 Mar 2020 07:34:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E0900206B1 for ; Fri, 13 Mar 2020 07:34:30 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="sV3fgjNC" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726393AbgCMHe3 (ORCPT ); Fri, 13 Mar 2020 03:34:29 -0400 Received: from mail-pl1-f196.google.com ([209.85.214.196]:40029 "EHLO mail-pl1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726216AbgCMHe3 (ORCPT ); Fri, 13 Mar 2020 03:34:29 -0400 Received: by mail-pl1-f196.google.com with SMTP id h11so3826014plk.7; Fri, 13 Mar 2020 00:34:29 -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:references:mime-version :content-disposition:in-reply-to:user-agent; bh=iqIrEWPHtK36KHL97scoySA1zOUO14/T0uQX8yO3Kk4=; b=sV3fgjNCxZa0NMDNX/eEDrLKybxnbFPT9ahm32wdl+TFAc79eudak0fkV/AKFyVMRK P5TaBgoZogmiAbxPUktzbaUZhrx8EAPNBjccwhvMxwKy+1g4Kk0npunlc4CjacaX34oj gtcK0uxZKjD8VMkA2Pi8s95+su1IwX4Z/3Gb30Vbu/nDu4rauGMf5po6aY/5v+2LrSEw wsC7TTAFZEVoyfFbqE2UEqbUyh+9VR02yTk+fOt7rbP+Jjt7HXbHqov2oyAaO6qo+ZX2 j8Ff3u6/i/TLJKw9AptcLT6l6lYnM3AM/rk3DFD9DUdphRcybMEKEQyzDzXzm/zoEmup Jdvw== 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:references :mime-version:content-disposition:in-reply-to:user-agent; bh=iqIrEWPHtK36KHL97scoySA1zOUO14/T0uQX8yO3Kk4=; b=EDJ6k7DLQlJZDNiKk9JYIFuRMdNdCnKsyA7YIystKS3RJ4QgN/6oW8g0GbDbAffdRW o1cV68o++y0tgTqwyZjJxLbjd0sTqRhHwrwDHe+37asp0b6RRy+a9CVqPjIqSGKVtxQ0 SfYE1XTjbFr5aTfzehMALuQNDe0xjODelxSCgOSA4hSjhYNW/mPzjT7ybQi246niqDsw ifN/mwjwpldwe4cKSn9XlQvyIkSco/zAhmp3zZXXzmEdTWquXZwWVaEM7WHS1WXJXJXb IVdOAjKJwoNsktBdlD+mbkR2V+0T4Nsn7tMm01ommJ7JCRWZL1ScPNyabF/ZwZ+zmd8W NmtQ== X-Gm-Message-State: ANhLgQ2fqIj/7t+1u/0lIOcytMKNKg0+R2dzfYu2jAd0VwLpQ2aKO/VT 0juH/BKNhbOL1DK5nki0pF4= X-Google-Smtp-Source: ADFU+vvt5Yz6wpzYZKQnDeW9SKZ45i0fLG+ULFfNUkt+9fPbu7uWpM9sM6imSkYH1mxkGqS/YrK5TA== X-Received: by 2002:a17:90b:1954:: with SMTP id nk20mr8418374pjb.69.1584084868541; Fri, 13 Mar 2020 00:34:28 -0700 (PDT) Received: from localhost ([2401:fa00:8f:203:5bbb:c872:f2b1:f53b]) by smtp.gmail.com with ESMTPSA id u11sm10965653pjn.2.2020.03.13.00.34.26 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 13 Mar 2020 00:34:27 -0700 (PDT) Date: Fri, 13 Mar 2020 16:34:25 +0900 From: Sergey Senozhatsky To: Bruno Meneguele Cc: linux-kernel@vger.kernel.org, stable@vger.kernel.org, pmladek@suse.com, sergey.senozhatsky@gmail.com, rostedt@goodmis.org Subject: Re: [PATCH] kernel/printk: add kmsg SEEK_CUR handling Message-ID: <20200313073425.GA219881@google.com> References: <20200313003533.2203429-1-bmeneg@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200313003533.2203429-1-bmeneg@redhat.com> User-Agent: Mutt/1.12.2 (2019-09-21) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On (20/03/12 21:35), Bruno Meneguele wrote: > > Userspace libraries, e.g. glibc's dprintf(), expect the default return value > for invalid seek situations: -ESPIPE, but when the IO was over /dev/kmsg the > current state of kernel code was returning the generic case of an -EINVAL. > Hence, userspace programs were not behaving as expected or documented. > Hmm. I don't think I see ESPIPE in documentation [0], [1], [2] [0] https://pubs.opengroup.org/onlinepubs/9699919799/functions/fprintf.html [1] http://man7.org/linux/man-pages/man3/dprintf.3p.html [2] http://man7.org/linux/man-pages/man3/fprintf.3p.html -ss