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=-2.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, 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 E0C16C3A5A2 for ; Tue, 3 Sep 2019 15:39:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B945523431 for ; Tue, 3 Sep 2019 15:39:35 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="PdKulyV7" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729485AbfICPjc (ORCPT ); Tue, 3 Sep 2019 11:39:32 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:53356 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727667AbfICPjb (ORCPT ); Tue, 3 Sep 2019 11:39:31 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=X/cB+D23nb3lX4M1niPmjOpwMGJ9zXCGneGvPXK49yk=; b=PdKulyV7w7y/A8JCioTeyJUuR y3Xccyj9G6xJF2RbjybT/K0F29/PFbSQafRj+pndk+/yoedkvuH6HVhD+zzptW42f6J2cebfVmilo UNCn4jitxx8GqoLqUeXZOioygfsc1XMfHMWCzocd0q7Urfh/oVU50o4uyCZT5QpB4l+l7s85hrNsg uGKJ4n6sUvDKSao5Au9nJQ2YGcmxOPY0AWIul0QyWh9AR42l4GbY4gzFykHKXbftY6tvnlAqs+7p2 C8UMMHkQWMBLyIS5XfOzykxhVUY1pjbdarKNnJY9X7cUBurB6BwqqGNengoL8WlmZQS9sUtZHwPNK s8MoEWvCA==; Received: from hch by bombadil.infradead.org with local (Exim 4.92 #3 (Red Hat Linux)) id 1i5Au2-0000xR-JZ; Tue, 03 Sep 2019 15:39:30 +0000 Date: Tue, 3 Sep 2019 08:39:30 -0700 From: Christoph Hellwig To: Al Viro Cc: Christoph Hellwig , Qian Cai , linux-fsdevel@vger.kernel.org, LKML , Linus Torvalds Subject: Re: "fs/namei.c: keep track of nd->root refcount status" causes boot panic Message-ID: <20190903153930.GA2791@infradead.org> References: <7C6CCE98-1E22-433C-BF70-A3CBCDED4635@lca.pw> <20190903123719.GF1131@ZenIV.linux.org.uk> <20190903130456.GA9567@infradead.org> <20190903134832.GH1131@ZenIV.linux.org.uk> <20190903135024.GA8274@infradead.org> <20190903135354.GI1131@ZenIV.linux.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190903135354.GI1131@ZenIV.linux.org.uk> User-Agent: Mutt/1.11.4 (2019-03-13) X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Tue, Sep 03, 2019 at 02:53:54PM +0100, Al Viro wrote: > On Tue, Sep 03, 2019 at 06:50:24AM -0700, Christoph Hellwig wrote: > > On Tue, Sep 03, 2019 at 02:48:32PM +0100, Al Viro wrote: > > > Not sure what would be the best way to do it... I don't mind breaking > > > the out-of-tree modules, whatever their license is; what I would rather > > > avoid is _quiet_ breaking of such. > > > > Any out of tree module running against an upstream kernel will need > > a recompile for a new version anyway. So I would not worry about it > > at all. > > There's much nastier situation than "new upstream kernel released, > need to rebuild" - it's bisect in mainline trying to locate something... I really don't get the point. And it's not like we've card about this anywhere else. And jumping wildly around with the numeric values for constants will lead to bugs like the one you added and fixed again and again.