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=-10.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=unavailable 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 D7141C56202 for ; Tue, 24 Nov 2020 10:28:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 548AB206D4 for ; Tue, 24 Nov 2020 10:28:52 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=alien8.de header.i=@alien8.de header.b="oxFEsy1x" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731296AbgKXK2R (ORCPT ); Tue, 24 Nov 2020 05:28:17 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33882 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726000AbgKXK2Q (ORCPT ); Tue, 24 Nov 2020 05:28:16 -0500 Received: from mail.skyhub.de (mail.skyhub.de [IPv6:2a01:4f8:190:11c2::b:1457]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0BE15C0613D6; Tue, 24 Nov 2020 02:28:16 -0800 (PST) Received: from zn.tnic (p200300ec2f0e360052021be21853ebf1.dip0.t-ipconnect.de [IPv6:2003:ec:2f0e:3600:5202:1be2:1853:ebf1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.skyhub.de (SuperMail on ZX Spectrum 128k) with ESMTPSA id 7F96F1EC0258; Tue, 24 Nov 2020 11:28:14 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=dkim; t=1606213694; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=c1iD6gApHU/j5+m+pR3M2pYpCc5CocFQKVTv8UeDApE=; b=oxFEsy1xk2af1Zv9kcv9IDxeON6BmmZshHoR+RFqMzeKov/OtvquRS1f0VwWN7SDXZuTBs 3tmvJmv3fWOjuMnLqJVmfbIBkUULqOJ4TdxeeMraENvmrx9cehfmVe5TWqwx/pVeyfrgxS i9wcUT2ECgbm5jEFSB/e5bSFj3iSOBw= Date: Tue, 24 Nov 2020 11:28:14 +0100 From: Borislav Petkov To: Jan Kara Cc: =?utf-8?B?UGF3ZcWC?= Jasiak , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, x86@kernel.org, Thomas Gleixner , Brian Gerst , Andy Lutomirski Subject: Re: PROBLEM: fanotify_mark EFAULT on x86 Message-ID: <20201124102814.GE4009@zn.tnic> References: <20201101212738.GA16924@gmail.com> <20201102122638.GB23988@quack2.suse.cz> <20201103211747.GA3688@gmail.com> <20201123164622.GJ27294@quack2.suse.cz> <20201123224651.GA27809@gmail.com> <20201124084507.GA4009@zn.tnic> <20201124102033.GA19336@quack2.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20201124102033.GA19336@quack2.suse.cz> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Nov 24, 2020 at 11:20:33AM +0100, Jan Kara wrote: > On Tue 24-11-20 09:45:07, Borislav Petkov wrote: > > On Mon, Nov 23, 2020 at 11:46:51PM +0100, Paweł Jasiak wrote: > > > On 23/11/20, Jan Kara wrote: > > > > OK, with a help of Boris Petkov I think I have a fix that looks correct > > > > (attach). Can you please try whether it works for you? Thanks! > > > > > > Unfortunately I am getting a linker error. > > > > > > ld: arch/x86/entry/syscall_32.o:(.rodata+0x54c): undefined reference to `__ia32_sys_ia32_fanotify_mark' > > > > Because CONFIG_COMPAT is not set in your .config. > > > > Jan, look at 121b32a58a3a and especially this hunk > > > > diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile > > index 9b294c13809a..b8f89f78b8cd 100644 > > --- a/arch/x86/kernel/Makefile > > +++ b/arch/x86/kernel/Makefile > > @@ -53,6 +53,8 @@ obj-y += setup.o x86_init.o i8259.o irqinit.o > > obj-$(CONFIG_JUMP_LABEL) += jump_label.o > > obj-$(CONFIG_IRQ_WORK) += irq_work.o > > obj-y += probe_roms.o > > +obj-$(CONFIG_X86_32) += sys_ia32.o > > +obj-$(CONFIG_IA32_EMULATION) += sys_ia32.o > > > > how it enables the ia32 syscalls depending on those config items. Now, > > you have > > > > #ifdef CONFIG_COMPAT > > -COMPAT_SYSCALL_DEFINE6(fanotify_mark, > > +SYSCALL_DEFINE6(ia32_fanotify_mark, > > > > which is under CONFIG_COMPAT which is not set in Paweł's config. > > > > config COMPAT > > def_bool y > > depends on IA32_EMULATION || X86_X32 > > > > but it depends on those two config items. > > > > However, it looks to me like ia32_fanotify_mark's definition should be > > simply under CONFIG_X86_32 because: > > > > IA32_EMULATION is 32-bit emulation on 64-bit kernels > > X86_X32 is for the x32 ABI > > Thanks for checking! I didn't realize I needed to change the ifdefs as well > (I missed that bit in 121b32a58a3a). So do I understand correctly that > whenever the kernel is 64-bit, 64-bit syscall args (e.g. defined as u64) are > passed just fine regardless of whether the userspace is 32-bit or not? > > Also how about other 32-bit archs? Because I now realized that > CONFIG_COMPAT as well as the COMPAT_SYSCALL_DEFINE6() is also utilized by > other 32-bit archs (I can see a reference to compat_sys_fanotify_mark e.g. > in sparc, powerpc, and other args). So I probably need to actually keep > that for other archs but do the modification only for x86, don't I? Hmm, you raise a good point and looking at that commit again, the intention is to supply those ia32 wrappers as both 32-bit native *and* 32-bit emulation ones. So I think this > -#ifdef CONFIG_COMPAT > +#if defined(CONFIG_COMPAT) || defined(CONFIG_X86_32) > +#ifdef CONFIG_X86_32 > +SYSCALL_DEFINE6(ia32_fanotify_mark, > +#elif CONFIG_COMPAT > COMPAT_SYSCALL_DEFINE6(fanotify_mark, > +#endif should be if defined(CONFIG_X86_32) || defined(CONFIG_IA32_EMULATION) SYSCALL_DEFINE6(ia32_fanotify_mark, #elif CONFIG_COMPAT COMPAT_SYSCALL_DEFINE6(fanotify_mark, #endif or so. Meaning that 32-bit native or 32-bit emulation supplies ia32_fanotify_mark() as a syscall wrapper and other arches doing CONFIG_COMPAT, still do the COMPAT_SYSCALL_DEFINE6() thing. But I'd prefer if someone more knowledgeable than me in that whole syscall macros muck to have a look... Thx. -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette