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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7E3C1EB64D9 for ; Thu, 29 Jun 2023 11:20:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232217AbjF2LUI (ORCPT ); Thu, 29 Jun 2023 07:20:08 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39672 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232161AbjF2LUF (ORCPT ); Thu, 29 Jun 2023 07:20:05 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8D90C2952 for ; Thu, 29 Jun 2023 04:20:04 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 2B0EF61522 for ; Thu, 29 Jun 2023 11:20:04 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 767FDC433C9; Thu, 29 Jun 2023 11:20:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1688037603; bh=lf5l31b+1kZiavyQaxGKgW6+S8GvQnNY9EfwHS/FG08=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=BmXsAdw9u/wZNr47deLpIkJwDF05eKVVVW4VdJjBvSas8kLgo7lQ0MjGOtNY551nu /lDN+b33Us14ekLWfAysN4RLbPZu5ujVD+uY+IbQonX+xD388seepMs+Li6yyOuIIV A1Y7rmEsm0JEHfEz2ok/JMiC7yAR7H3ntC97aUe3ZL1IWgNcc4Z6hJ8fbfJb8qlWVs G3lcapwNdAH2G0nqNmwGSdfdNXWFCRTLl7cRhy+NrpHkvPOx7ennP3IstMf5wlenZq wpphq4DGocW0mR4aR8Vru+nhW/sgfbGM3l3sWWdnso/EhNfQ+VzxIi5Pu1w6GAwCYd B3iBJXoEjASgw== Date: Thu, 29 Jun 2023 13:19:59 +0200 From: Christian Brauner To: =?utf-8?B?QmrDtnJuIFTDtnBlbA==?= Cc: syzbot , linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com Subject: Re: [syzbot] [kernel?] upstream test error: UBSAN: array-index-out-of-bounds in alloc_pid Message-ID: <20230629-ozonkonzentration-elche-0484e2c863dc@brauner> References: <000000000000dde2fb05ff2d39c6@google.com> <87352a7dwe.fsf@all.your.base.are.belong.to.us> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <87352a7dwe.fsf@all.your.base.are.belong.to.us> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jun 29, 2023 at 12:37:21PM +0200, Björn Töpel wrote: > syzbot writes: > > > Hello, > > > > syzbot found the following issue on: > > > > HEAD commit: 6aeadf7896bf Merge tag 'docs-arm64-move' of git://git.lwn... > > git tree: upstream > > console output: https://syzkaller.appspot.com/x/log.txt?x=12cea2c7280000 > > kernel config: https://syzkaller.appspot.com/x/.config?x=652d39e0420afbb8 > > dashboard link: https://syzkaller.appspot.com/bug?extid=522a57d8d5a0f7ac5c6c > > compiler: Debian clang version 15.0.7, GNU ld (GNU Binutils for Debian) 2.35.2 > > > > Downloadable assets: > > disk image: https://storage.googleapis.com/syzbot-assets/3887d048a41c/disk-6aeadf78.raw.xz > > vmlinux: https://storage.googleapis.com/syzbot-assets/b25a7d5f9034/vmlinux-6aeadf78.xz > > kernel image: https://storage.googleapis.com/syzbot-assets/96457fbed62d/bzImage-6aeadf78.xz > > > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > > Reported-by: syzbot+522a57d8d5a0f7ac5c6c@syzkaller.appspotmail.com > > > > ================================================================================ > > UBSAN: array-index-out-of-bounds in kernel/pid.c:244:3 > > index 1 is out of range for type 'struct upid[1]' > > CPU: 1 PID: 4996 Comm: syz-executor.0 Not tainted 6.4.0-syzkaller-01761-g6aeadf7896bf #0 > > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/27/2023 > > Call Trace: > > > > __dump_stack lib/dump_stack.c:88 [inline] > > dump_stack_lvl+0x1e7/0x2d0 lib/dump_stack.c:106 > > ubsan_epilogue lib/ubsan.c:217 [inline] > > __ubsan_handle_out_of_bounds+0x11c/0x150 lib/ubsan.c:348 > > alloc_pid+0x405/0xc40 kernel/pid.c:244 > > copy_process+0x1f2f/0x4350 kernel/fork.c:2523 > > kernel_clone+0x222/0x800 kernel/fork.c:2915 > > __do_sys_clone kernel/fork.c:3058 [inline] > > __se_sys_clone kernel/fork.c:3042 [inline] > > __x64_sys_clone+0x258/0x2a0 kernel/fork.c:3042 > > do_syscall_x64 arch/x86/entry/common.c:50 [inline] > > do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80 > > entry_SYSCALL_64_after_hwframe+0x63/0xcd > > RIP: 0033:0x7f30e5e89fab > > Code: ed 0f 85 60 01 00 00 64 4c 8b 0c 25 10 00 00 00 45 31 c0 4d 8d 91 d0 02 00 00 31 d2 31 f6 bf 11 00 20 01 b8 38 00 00 00 0f 05 <48> 3d 00 f0 ff ff 0f 87 89 00 00 00 41 89 c5 85 c0 0f 85 90 00 00 > > RSP: 002b:00007ffe72312890 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 > > RAX: ffffffffffffffda RBX: 00007ffe72312ee8 RCX: 00007f30e5e89fab > > RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 > > RBP: 0000000000000000 R08: 0000000000000000 R09: 000055555643c400 > > R10: 000055555643c6d0 R11: 0000000000000246 R12: 0000000000000000 > > R13: 00007ffe72312980 R14: 00007f30e5fac9d8 R15: 000000000000000c > > > > ================================================================================ > > FWIW, I hit this with the clone3 kselftest (on riscv). This is caused by not using a proper flexible array member for struct upid in struct pid. I sent a pull request with Kees' fix for this yesterday.