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=-5.3 required=3.0 tests=BAYES_00, 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 665A5C433E0 for ; Tue, 16 Mar 2021 15:35:54 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id F2F08650EB for ; Tue, 16 Mar 2021 15:35:53 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org F2F08650EB Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.crashing.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 7BEDC8D0003; Tue, 16 Mar 2021 11:35:53 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 76DF48D0001; Tue, 16 Mar 2021 11:35:53 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 636298D0003; Tue, 16 Mar 2021 11:35:53 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0157.hostedemail.com [216.40.44.157]) by kanga.kvack.org (Postfix) with ESMTP id 46F858D0001 for ; Tue, 16 Mar 2021 11:35:53 -0400 (EDT) Received: from smtpin18.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id EBEFB180AD838 for ; Tue, 16 Mar 2021 15:35:52 +0000 (UTC) X-FDA: 77926137744.18.ED1B1CF Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) by imf15.hostedemail.com (Postfix) with ESMTP id 0D16EA004CCB for ; Tue, 16 Mar 2021 15:35:46 +0000 (UTC) Received: from gate.crashing.org (localhost.localdomain [127.0.0.1]) by gate.crashing.org (8.14.1/8.14.1) with ESMTP id 12GFXL1m029361; Tue, 16 Mar 2021 10:33:21 -0500 Received: (from segher@localhost) by gate.crashing.org (8.14.1/8.14.1/Submit) id 12GFXL3d029359; Tue, 16 Mar 2021 10:33:21 -0500 X-Authentication-Warning: gate.crashing.org: segher set sender to segher@kernel.crashing.org using -f Date: Tue, 16 Mar 2021 10:33:20 -0500 From: Segher Boessenkool To: Christophe Leroy Cc: Alexander Potapenko , Marco Elver , Andrew Morton , Dmitriy Vyukov , Andrey Konovalov , Jann Horn , LKML , Linux Memory Management List , kasan-dev Subject: Re: [PATCH mm] kfence: fix printk format for ptrdiff_t Message-ID: <20210316153320.GF16691@gate.crashing.org> References: <20210303121157.3430807-1-elver@google.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4.2.3i X-Stat-Signature: br7jj73wd49abjdz5pkwfqws4kmc46rp X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 0D16EA004CCB Received-SPF: none (kernel.crashing.org>: No applicable sender policy available) receiver=imf15; identity=mailfrom; envelope-from=""; helo=gate.crashing.org; client-ip=63.228.1.57 X-HE-DKIM-Result: none/none X-HE-Tag: 1615908946-511551 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Tue, Mar 16, 2021 at 09:32:32AM +0100, Christophe Leroy wrote: > +segher I cannot see through the wood of #defines here, sorry. > Still a problem. > > I don't understand, gcc bug ? Rule #1: If you do not understand what is happening, it is not a compiler bug. I'm not saying that it isn't, just that it is much more likely something else. > The offending argument is 'const ptrdiff_t object_index' > > We have: > > arch/powerpc/include/uapi/asm/posix_types.h:typedef long > __kernel_ptrdiff_t; So this is a 64-bit build. > include/linux/types.h:typedef __kernel_ptrdiff_t ptrdiff_t; > > And get: > > CC mm/kfence/report.o > In file included from ./include/linux/printk.h:7, > from ./include/linux/kernel.h:16, > from mm/kfence/report.c:10: > mm/kfence/report.c: In function 'kfence_report_error': > ./include/linux/kern_levels.h:5:18: warning: format '%td' expects argument > of type 'ptrdiff_t', but argument 6 has type 'long int' [-Wformat=] This is declared as const ptrdiff_t object_index = meta ? meta - kfence_metadata : -1; so maybe something with that goes wrong? What happens if you delete the (useless) "const" here? Segher