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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6C0F0CA0FFE for ; Tue, 5 Sep 2023 16:34:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244572AbjIEQer (ORCPT ); Tue, 5 Sep 2023 12:34:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40960 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1354513AbjIEMKK (ORCPT ); Tue, 5 Sep 2023 08:10:10 -0400 Received: from wp530.webpack.hosteurope.de (wp530.webpack.hosteurope.de [80.237.130.52]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 470361AB; Tue, 5 Sep 2023 05:10:07 -0700 (PDT) Received: from [2a02:8108:8980:2478:8cde:aa2c:f324:937e]; authenticated by wp530.webpack.hosteurope.de running ExIM with esmtpsa (TLS1.3:ECDHE_RSA_AES_128_GCM_SHA256:128) id 1qdUsf-0006J5-Ge; Tue, 05 Sep 2023 14:10:05 +0200 Message-ID: <1d79cc64-46d8-42ab-8219-e45e8d19532f@leemhuis.info> Date: Tue, 5 Sep 2023 14:10:04 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: Don't fill the kernel log with memfd_create messages Content-Language: en-US, de-DE To: Linux kernel regressions list Cc: stable@vger.kernel.org, linux-api@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org References: <1693408388.rwssx8r1h9.none.ref@localhost> <1693408388.rwssx8r1h9.none@localhost> <14b4a922-a31a-a329-0264-3d8bd101ee6b@suse.cz> From: "Linux regression tracking #update (Thorsten Leemhuis)" Reply-To: Linux regressions mailing list In-Reply-To: <14b4a922-a31a-a329-0264-3d8bd101ee6b@suse.cz> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-bounce-key: webpack.hosteurope.de;regressions@leemhuis.info;1693915807;afc559ae; X-HE-SMSGID: 1qdUsf-0006J5-Ge Precedence: bulk List-ID: X-Mailing-List: linux-api@vger.kernel.org [TLDR: This mail in primarily relevant for Linux kernel regression tracking. See link in footer if these mails annoy you.] On 04.09.23 15:31, Vlastimil Babka wrote: > On 8/30/23 17:52, Alex Xu (Hello71) wrote: >> Hi all, >> >> Recently "memfd: improve userspace warnings for missing exec-related >> flags" was merged. On my system, this is a regression, not an >> improvement, because the entire 256k kernel log buffer (default on x86) >> is filled with these warnings and "__do_sys_memfd_create: 122 callbacks >> suppressed". I haven't investigated too closely, but the most likely >> cause is Wayland libraries. >> >> This is too serious of a consequence for using an old API, especially >> considering how recently the flags were added. The vast majority of >> software has not had time to add the flags: glibc does not define the >> macros until 2.38 which was released less than one month ago, man-pages >> does not document the flags, and according to Debian Code Search, only >> systemd, stress-ng, and strace actually pass either of these flags. >> >> Furthermore, since old kernels reject unknown flags, it's not just a >> matter of defining and passing the flag; every program needs to >> add logic to handle EINVAL and try again. >> >> Some other way needs to be found to encourage userspace to add the >> flags; otherwise, this message will be patched out because the kernel >> log becomes unusable after running unupdated programs, which will still >> exist even after upstreams are fixed. In particular, AppImages, >> flatpaks, snaps, and similar app bundles contain vendored Wayland >> libraries which can be difficult or impossible to update. > > It's being reverted: > https://lore.kernel.org/all/20230902230530.6B663C433C8@smtp.kernel.org/ in that case: #regzbot fix: revert "memfd: improve userspace warnings for missing exec-related flags". #regzbot ignore-activity Ciao, Thorsten (wearing his 'the Linux kernel's regression tracker' hat) -- Everything you wanna know about Linux kernel regression tracking: https://linux-regtracking.leemhuis.info/about/#tldr That page also explains what to do if mails like this annoy you.