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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 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 2DD6BC10F14 for ; Tue, 8 Oct 2019 09:19:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0DECB20673 for ; Tue, 8 Oct 2019 09:19:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730147AbfJHJT2 (ORCPT ); Tue, 8 Oct 2019 05:19:28 -0400 Received: from relay1-d.mail.gandi.net ([217.70.183.193]:51607 "EHLO relay1-d.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728866AbfJHJT2 (ORCPT ); Tue, 8 Oct 2019 05:19:28 -0400 X-Originating-IP: 81.185.172.69 Received: from [192.168.43.237] (69.172.185.81.rev.sfr.net [81.185.172.69]) (Authenticated sender: alex@ghiti.fr) by relay1-d.mail.gandi.net (Postfix) with ESMTPSA id E4DD724000F; Tue, 8 Oct 2019 09:19:17 +0000 (UTC) From: Alex Ghiti To: Atish Patra Cc: "keescook@chromium.org" , "ralf@linux-mips.org" , "palmer@sifive.com" , "aou@eecs.berkeley.edu" , "linux-kernel@vger.kernel.org" , "catalin.marinas@arm.com" , "paul.walmsley@sifive.com" , "paul.burton@mips.com" , "linux@armlinux.org.uk" , "linux-mm@kvack.org" , "hch@lst.de" , "will.deacon@arm.com" , "viro@zeniv.linux.org.uk" , "jhogan@kernel.org" , "linux-fsdevel@vger.kernel.org" , "mcgrof@kernel.org" , "linux-riscv@lists.infradead.org" , "linux-arm-kernel@lists.infradead.org" , "akpm@linux-foundation.org" Subject: Re: [PATCH v6 14/14] riscv: Make mmap allocation top-down by default References: <20190808061756.19712-1-alex@ghiti.fr> <20190808061756.19712-15-alex@ghiti.fr> <208433f810b5b07b1e679d7eedb028697dff851b.camel@wdc.com> <60b52f20-a2c7-dee9-7cf3-a727f07400b9@ghiti.fr> Message-ID: Date: Tue, 8 Oct 2019 05:19:16 -0400 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: <60b52f20-a2c7-dee9-7cf3-a727f07400b9@ghiti.fr> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/7/19 5:11 AM, Alex Ghiti wrote: > On 10/4/19 10:12 PM, Atish Patra wrote: >> On Thu, 2019-08-08 at 02:17 -0400, Alexandre Ghiti wrote: >>> In order to avoid wasting user address space by using bottom-up mmap >>> allocation scheme, prefer top-down scheme when possible. >>> >>> Before: >>> root@qemuriscv64:~# cat /proc/self/maps >>> 00010000-00016000 r-xp 00000000 fe:00 6389 /bin/cat.coreutils >>> 00016000-00017000 r--p 00005000 fe:00 6389 /bin/cat.coreutils >>> 00017000-00018000 rw-p 00006000 fe:00 6389 /bin/cat.coreutils >>> 00018000-00039000 rw-p 00000000 00:00 0          [heap] >>> 1555556000-155556d000 r-xp 00000000 fe:00 7193 /lib/ld-2.28.so >>> 155556d000-155556e000 r--p 00016000 fe:00 7193 /lib/ld-2.28.so >>> 155556e000-155556f000 rw-p 00017000 fe:00 7193 /lib/ld-2.28.so >>> 155556f000-1555570000 rw-p 00000000 00:00 0 >>> 1555570000-1555572000 r-xp 00000000 00:00 0      [vdso] >>> 1555574000-1555576000 rw-p 00000000 00:00 0 >>> 1555576000-1555674000 r-xp 00000000 fe:00 7187 /lib/libc-2.28.so >>> 1555674000-1555678000 r--p 000fd000 fe:00 7187 /lib/libc-2.28.so >>> 1555678000-155567a000 rw-p 00101000 fe:00 7187 /lib/libc-2.28.so >>> 155567a000-15556a0000 rw-p 00000000 00:00 0 >>> 3fffb90000-3fffbb1000 rw-p 00000000 00:00 0      [stack] >>> >>> After: >>> root@qemuriscv64:~# cat /proc/self/maps >>> 00010000-00016000 r-xp 00000000 fe:00 6389 /bin/cat.coreutils >>> 00016000-00017000 r--p 00005000 fe:00 6389 /bin/cat.coreutils >>> 00017000-00018000 rw-p 00006000 fe:00 6389 /bin/cat.coreutils >>> 2de81000-2dea2000 rw-p 00000000 00:00 0          [heap] >>> 3ff7eb6000-3ff7ed8000 rw-p 00000000 00:00 0 >>> 3ff7ed8000-3ff7fd6000 r-xp 00000000 fe:00 7187 /lib/libc-2.28.so >>> 3ff7fd6000-3ff7fda000 r--p 000fd000 fe:00 7187 /lib/libc-2.28.so >>> 3ff7fda000-3ff7fdc000 rw-p 00101000 fe:00 7187 /lib/libc-2.28.so >>> 3ff7fdc000-3ff7fe2000 rw-p 00000000 00:00 0 >>> 3ff7fe4000-3ff7fe6000 r-xp 00000000 00:00 0      [vdso] >>> 3ff7fe6000-3ff7ffd000 r-xp 00000000 fe:00 7193 /lib/ld-2.28.so >>> 3ff7ffd000-3ff7ffe000 r--p 00016000 fe:00 7193 /lib/ld-2.28.so >>> 3ff7ffe000-3ff7fff000 rw-p 00017000 fe:00 7193 /lib/ld-2.28.so >>> 3ff7fff000-3ff8000000 rw-p 00000000 00:00 0 >>> 3fff888000-3fff8a9000 rw-p 00000000 00:00 0      [stack] >>> >>> Signed-off-by: Alexandre Ghiti >>> Acked-by: Paul Walmsley >>> Reviewed-by: Christoph Hellwig >>> Reviewed-by: Kees Cook >>> Reviewed-by: Luis Chamberlain >>> --- >>>   arch/riscv/Kconfig | 12 ++++++++++++ >>>   1 file changed, 12 insertions(+) >>> >>> diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig >>> index 59a4727ecd6c..87dc5370becb 100644 >>> --- a/arch/riscv/Kconfig >>> +++ b/arch/riscv/Kconfig >>> @@ -54,6 +54,18 @@ config RISCV >>>       select EDAC_SUPPORT >>>       select ARCH_HAS_GIGANTIC_PAGE >>>       select ARCH_WANT_HUGE_PMD_SHARE if 64BIT >>> +    select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT if MMU >>> +    select HAVE_ARCH_MMAP_RND_BITS >>> + >>> +config ARCH_MMAP_RND_BITS_MIN >>> +    default 18 if 64BIT >>> +    default 8 >>> + >>> +# max bits determined by the following formula: >>> +#  VA_BITS - PAGE_SHIFT - 3 >>> +config ARCH_MMAP_RND_BITS_MAX >>> +    default 24 if 64BIT # SV39 based >>> +    default 17 >>>     config MMU >>>       def_bool y >> With this patch, I am not able to boot a Fedora Linux(a Gnome desktop >> image) on RISC-V hardware (Unleashed + Microsemi Expansion board). The >> booting gets stuck right after systemd starts. >> >> https://paste.fedoraproject.org/paste/TOrUMqqKH-pGFX7CnfajDg >> >> Reverting just this patch allow to boot Fedora successfully on specific >> RISC-V hardware. I have not root caused the issue but it looks like it >> might have messed userpsace mapping. > > It might have messed userspace mapping but not enough to make > userspace completely broken > as systemd does some things. I would try to boot in legacy layout: if > you can try to set sysctl legacy_va_layout > at boottime, it will map userspace as it was before (bottom-up). If > that does not work, the problem could > be the randomization that is activated by default now. > Anyway, it's weird since userspace should not depend on how the > mapping is. > > If you can identify the program that stalls, that would be fantastic :) > > As the code is common to mips and arm now and I did not hear from > them, I imagine the problem comes > from us. > > Alex Atish, do you have any news regarding this problem ? If you have an image I can execute on qemu that reproduces the issue, I can take a look. Alex >> >