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=-11.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,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 A9E81C2BA1A for ; Mon, 6 Apr 2020 02:06:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8265820678 for ; Mon, 6 Apr 2020 02:06:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726512AbgDFCEy (ORCPT ); Sun, 5 Apr 2020 22:04:54 -0400 Received: from zeniv.linux.org.uk ([195.92.253.2]:45788 "EHLO ZenIV.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726373AbgDFCEy (ORCPT ); Sun, 5 Apr 2020 22:04:54 -0400 Received: from viro by ZenIV.linux.org.uk with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1jLH87-00BimU-Nh; Mon, 06 Apr 2020 02:04:51 +0000 Date: Mon, 6 Apr 2020 03:04:51 +0100 From: Al Viro To: kernel test robot Cc: LKML , lkp@lists.01.org Subject: Re: [non] 2aa3847085: will-it-scale.per_process_ops -32.0% regression Message-ID: <20200406020451.GQ23230@ZenIV.linux.org.uk> References: <20200406012539.GR8179@shao2-debian> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200406012539.GR8179@shao2-debian> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Apr 06, 2020 at 09:25:39AM +0800, kernel test robot wrote: > Greeting, > > FYI, we noticed a -32.0% regression of will-it-scale.per_process_ops due to commit: > > > commit: 2aa38470853a65dc9b1b4bd0989d34cd3fc57ebd ("non-RCU analogue of the previous commit") > https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git master Arrgghh... Could you check if vfs.git#fixes recovers that? FWIW, proposed fix is this: commit d98d78cd6ac9eb5ed0506140cc43432d7c7dd480 Author: Al Viro Date: Sun Apr 5 21:59:55 2020 -0400 fix braino in legitimize_path() brown paperbag time... wrong order of arguments ended up confusing the values to check dentry and mount_lock seqcounts against. Reported-by: kernel test robot Fixes: 2aa38470853a ("non-RCU analogue of the previous commit") Signed-off-by: Al Viro diff --git a/fs/namei.c b/fs/namei.c index 61fdb77a7d58..a320371899cf 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -610,7 +610,7 @@ static bool __legitimize_path(struct path *path, unsigned seq, unsigned mseq) static inline bool legitimize_path(struct nameidata *nd, struct path *path, unsigned seq) { - return __legitimize_path(path, nd->m_seq, seq); + return __legitimize_path(path, seq, nd->m_seq); } static bool legitimize_links(struct nameidata *nd)