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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 90908EDEBFA for ; Tue, 3 Mar 2026 21:53:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date: Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=D1r1C1nkJC8myDUqBbWlJuno+S+Hsv+z3MI/a3FcqHc=; b=bZ2p+c7sLjNUeCE3QRRz5Ys1bR hgYPl0Sekq1LQ5W4IMY9kciuyRhUT/W5OZGULzzurvQvlll6s2KeawOq4V4hzGC7LDKebq7Z8g3J2 BALiqJVClN+GkCWscNQNZc5/D7cQxntaJKsTWB4ZbaxZ7wzqjeCt1Gnrwy4r/Kt1TrSS2P0hNbhg9 80fzUxTG12xnQ4yKFAQmS0V5ezX5pUqS+BeMUmIBmV0sXhaCdpfyvSoAnvNU8cTnUeqBLHbPWiGsc nxl8ToqRjcExtiQRsY1xatsA7B32SlWhxgj9i03V6zD6vu2FcXqhIG/YyYcjlGck0lASG9aoVOxtt xYh17mRg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vxXgU-0000000G0Nd-11U6; Tue, 03 Mar 2026 21:53:42 +0000 Received: from terminus.zytor.com ([2607:7c80:54:3::136] helo=mail.zytor.com) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1vxXgQ-0000000G0N7-3dpw for linux-arm-kernel@lists.infradead.org; Tue, 03 Mar 2026 21:53:40 +0000 Received: from [172.27.2.41] (c-76-133-66-138.hsd1.ca.comcast.net [76.133.66.138]) (authenticated bits=0) by mail.zytor.com (8.18.1/8.17.1) with ESMTPSA id 623LavOS3436858 (version=TLSv1.3 cipher=TLS_AES_128_GCM_SHA256 bits=128 verify=NO); Tue, 3 Mar 2026 13:36:57 -0800 DKIM-Filter: OpenDKIM Filter v2.11.0 mail.zytor.com 623LavOS3436858 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=zytor.com; s=2026022301; t=1772573825; bh=D1r1C1nkJC8myDUqBbWlJuno+S+Hsv+z3MI/a3FcqHc=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=RLwZ/rk8vaq6V4tFXUGKShs9EBYHpeXArYtAO8GRTPF0Qb9ckRJAy3tcD5EWeuBHX vr0OB9eU7N3DVYjRVanoVDfqhq4F+AkTzExopgowDGEFypgJWOgNXBkU6FNdThL97f Lw7JtD6O+ENFjRKkORJY5LGdYpcgeiUuBzkeJbD5nNV5qeKq9oq8xMw9GJMwXTJY58 GQjC3/XyTBNrpt/UhJOXTqWbTWEJKRY1JmqsyxsLflRD6J85F4d6toUWrWmiKQly38 ciLSIrOtlh968Kr67YxA/mjWIPI5I11u1R6hN8+kq3t5kAbHjJDAA+e6EhT7AmEGux lOCVXVCJis+ZQ== Message-ID: <0d2d834d-0f3c-43bb-9530-da6c2492763a@zytor.com> Date: Tue, 3 Mar 2026 13:36:52 -0800 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 1/7] x86/vdso: Respect COMPAT_32BIT_TIME To: Arnd Bergmann , =?UTF-8?Q?Thomas_Wei=C3=9Fschuh?= Cc: Andy Lutomirski , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, Russell King , Catalin Marinas , Will Deacon , Madhavan Srinivasan , Michael Ellerman , Nicholas Piggin , Christophe Leroy , Thomas Bogendoerfer , Vincenzo Frascino , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, linux-mips@vger.kernel.org References: <20260227-vdso-compat_32bit_time-v1-0-3f0286a7bac3@linutronix.de> <20260227-vdso-compat_32bit_time-v1-1-3f0286a7bac3@linutronix.de> <03cd1e21-a2f2-46a1-a674-cbaef9712016@app.fastmail.com> <20260227103226-cc3bb32c-0107-4c09-b81a-ca33ea03ad5c@linutronix.de> <49b7c9f9-198a-49f7-880b-6ae74d7bd985@zytor.com> <2b1ac7b9-fcc8-4aa3-a0ad-eb37e4bce030@app.fastmail.com> <56591FD5-0DD0-4117-BC7B-4565E3F6512E@zytor.com> Content-Language: en-US, sv-SE From: "H. Peter Anvin" In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260303_135339_340124_BCC83043 X-CRM114-Status: GOOD ( 11.89 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 2026-03-03 13:27, Arnd Bergmann wrote: > > I see. I would argue here that a link failure is actually the best > case then: the entire point of CONFIG_COMPAT_32BIT_TIME=n is to > enforce the fail-early case, as opposed to silent data corruption > after (now) 12 years of operation. > > I don't think there is an actual link failure here, as dl_vdso_vsym() > resolves it at runtime by glibc (when using time32), while musl > doesn't use __vdso_gettimeofday at all. > Well, the former is a link failure -- just one handled reasonably gracefully. A library that really wants a fallback can presumably also avoid the problem by provide a weak reference for the fallback. -hpa