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=-15.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 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 EE31BC433E0 for ; Thu, 11 Mar 2021 19:39:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id ACC5964F73 for ; Thu, 11 Mar 2021 19:39:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229871AbhCKTj1 (ORCPT ); Thu, 11 Mar 2021 14:39:27 -0500 Received: from pegase1.c-s.fr ([93.17.236.30]:41174 "EHLO pegase1.c-s.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229796AbhCKTjJ (ORCPT ); Thu, 11 Mar 2021 14:39:09 -0500 Received: from localhost (mailhub1-int [192.168.12.234]) by localhost (Postfix) with ESMTP id 4DxK554JMmz9typl; Thu, 11 Mar 2021 20:39:05 +0100 (CET) X-Virus-Scanned: Debian amavisd-new at c-s.fr Received: from pegase1.c-s.fr ([192.168.12.234]) by localhost (pegase1.c-s.fr [192.168.12.234]) (amavisd-new, port 10024) with ESMTP id 6Iqq4qYKiOTw; Thu, 11 Mar 2021 20:39:05 +0100 (CET) Received: from messagerie.si.c-s.fr (messagerie.si.c-s.fr [192.168.25.192]) by pegase1.c-s.fr (Postfix) with ESMTP id 4DxK551CyCz9typk; Thu, 11 Mar 2021 20:39:05 +0100 (CET) Received: from localhost (localhost [127.0.0.1]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 1BB0F8B80D; Thu, 11 Mar 2021 20:39:07 +0100 (CET) X-Virus-Scanned: amavisd-new at c-s.fr Received: from messagerie.si.c-s.fr ([127.0.0.1]) by localhost (messagerie.si.c-s.fr [127.0.0.1]) (amavisd-new, port 10023) with ESMTP id 9oXY_QXeLpW6; Thu, 11 Mar 2021 20:39:07 +0100 (CET) Received: from [192.168.4.90] (unknown [192.168.4.90]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 925208B80B; Thu, 11 Mar 2021 20:39:06 +0100 (CET) Subject: Re: [PATCH v2 25/43] powerpc/32: Replace ASM exception exit by C exception exit from ppc64 To: Michael Ellerman , Benjamin Herrenschmidt , Paul Mackerras , npiggin@gmail.com Cc: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org References: <87tuphkdkz.fsf@mpe.ellerman.id.au> From: Christophe Leroy Message-ID: <0296d1bc-b37e-43c8-06cf-00ec458fb74e@csgroup.eu> Date: Thu, 11 Mar 2021 20:39:04 +0100 User-Agent: Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.8.0 MIME-Version: 1.0 In-Reply-To: <87tuphkdkz.fsf@mpe.ellerman.id.au> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: fr Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Le 11/03/2021 à 14:46, Michael Ellerman a écrit : > Christophe Leroy writes: >> This patch replaces the PPC32 ASM exception exit by C exception exit. >> >> Signed-off-by: Christophe Leroy >> --- >> arch/powerpc/kernel/entry_32.S | 481 +++++++++----------------------- >> arch/powerpc/kernel/interrupt.c | 4 + >> 2 files changed, 132 insertions(+), 353 deletions(-) > > Bisect points to this breaking qemu mac99 for me, with pmac32_defconfig. > > I haven't had time to dig any deeper sorry. Embarrasing ... I don't get this problem on the 8xx (nohash/32) or the 83xx (book3s/32). I don't get this problem with qemu mac99 when using my klibc-based initramfs. I managed to reproduce it with the rootfs.cpio that I got some time ago from linuxppc github Wiki. I'll investigate it tomorrow. Thanks Christophe > > cheers > > > Freeing unused kernel memory: 1132K > This architecture does not have kernel memory protection. > Run /init as init process > init[1]: User access of kernel address (fffffd20) - exploit attempt? (uid: 0) > init[1]: segfault (11) at fffffd20 nip b7e78638 lr b7e845e4 code 1 in ld-2.27.so[b7e6b000+22000] > init[1]: code: 92010080 92210084 92410088 92810090 92a10094 92c10098 930100a0 932100a4 > init[1]: code: 934100a8 936100ac 93a100b4 91810074 <7d41496e> 39400000 3b810017 579c0036 > Kernel panic - not syncing: Attempted to kill init! exitcode=0x00ERROR: Error: saw oops/warning etc. while expecting > 00000b > CPU: 0 PID: 1 Comm: init Not tainted 5.12.0-rc2+ #1 > Call Trace: > [f1019d80] [c004f1ec] panic+0x138/0x328 (unreliable) > [f1019de0] [c0051c8c] do_exit+0x880/0x8f4 > [f1019e30] [c0052bdc] do_group_exit+0x40/0xa4 > [f1019e50] [c0060d04] get_signal+0x1e8/0x834 > [f1019eb0] [c000b624] do_notify_resume+0xc8/0x314 > [f1019f10] [c0010da8] interrupt_exit_user_prepare+0xa4/0xdc > [f1019f30] [c0018228] interrupt_return+0x14/0x14c > --- interrupt: 300 at 0xb7e78638 > NIP: b7e78638 LR: b7e845e4 CTR: c01ea2d8 > REGS: f1019f40 TRAP: 0300 Not tainted (5.12.0-rc2+) > MSR: 0000d032 CR: 28004422 XER: 20000000 > DAR: fffffd20 DSISR: 42000000 > GPR00: b7e845e4 bf951440 00000000 bf951460 00000000 bf951718 fefefeff 7f7f7f7f > GPR08: bf9516b0 406ae8e0 b7eac1d4 00000000 0a12247b 00000000 b7e8a0d0 b7e78554 > GPR16: bf951730 bf9516f0 b7eaaf40 bf9516f0 00000001 b7eaa688 10002178 bf951460 > GPR24: 00000000 00000000 b7eac200 100cff38 bf9516f0 10002179 b7e845e4 bf951440 > NIP [b7e78638] 0xb7e78638 > LR [b7e845e4] 0xb7e845e4 > --- interrupt: 300 > Rebooting in 180 seconds.. >