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 018A5C433FE for ; Thu, 10 Feb 2022 08:27:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237342AbiBJI1L (ORCPT ); Thu, 10 Feb 2022 03:27:11 -0500 Received: from mxb-00190b01.gslb.pphosted.com ([23.128.96.19]:58110 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237337AbiBJI1L (ORCPT ); Thu, 10 Feb 2022 03:27:11 -0500 X-Greylist: delayed 895 seconds by postgrey-1.37 at lindbergh.monkeyblade.net; Thu, 10 Feb 2022 00:27:12 PST Received: from 1wt.eu (wtarreau.pck.nerim.net [62.212.114.60]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 37ECE109E; Thu, 10 Feb 2022 00:27:11 -0800 (PST) Received: (from willy@localhost) by pcw.home.local (8.15.2/8.15.2/Submit) id 21A8BQTo004763; Thu, 10 Feb 2022 09:11:26 +0100 Date: Thu, 10 Feb 2022 09:11:26 +0100 From: Willy Tarreau To: syzbot Cc: akpm@linux-foundation.org, andrii@kernel.org, ast@kernel.org, bjorn.topel@gmail.com, bjorn.topel@intel.com, bjorn@kernel.org, bpf@vger.kernel.org, daniel@iogearbox.net, davem@davemloft.net, fgheet255t@gmail.com, hawk@kernel.org, john.fastabend@gmail.com, jonathan.lemon@gmail.com, kafai@fb.com, kpsingh@kernel.org, kuba@kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, magnus.karlsson@intel.com, mudongliangabcd@gmail.com, netdev@vger.kernel.org, songliubraving@fb.com, syzkaller-bugs@googlegroups.com, torvalds@linux-foundation.org, yhs@fb.com Subject: Re: [syzbot] WARNING: kmalloc bug in xdp_umem_create (2) Message-ID: <20220210081125.GA4616@1wt.eu> References: <000000000000a3571605d27817b5@google.com> <0000000000001f60ef05d7a3c6ad@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <0000000000001f60ef05d7a3c6ad@google.com> User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Wed, Feb 09, 2022 at 10:08:07PM -0800, syzbot wrote: > syzbot has bisected this issue to: > > commit 7661809d493b426e979f39ab512e3adf41fbcc69 > Author: Linus Torvalds > Date: Wed Jul 14 16:45:49 2021 +0000 > > mm: don't allow oversized kvmalloc() calls > > bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=13bc74c2700000 > start commit: f4bc5bbb5fef Merge tag 'nfsd-5.17-2' of git://git.kernel.o.. > git tree: upstream > final oops: https://syzkaller.appspot.com/x/report.txt?x=107c74c2700000 > console output: https://syzkaller.appspot.com/x/log.txt?x=17bc74c2700000 > kernel config: https://syzkaller.appspot.com/x/.config?x=5707221760c00a20 > dashboard link: https://syzkaller.appspot.com/bug?extid=11421fbbff99b989670e > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=12e514a4700000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=15fcdf8a700000 > > Reported-by: syzbot+11421fbbff99b989670e@syzkaller.appspotmail.com > Fixes: 7661809d493b ("mm: don't allow oversized kvmalloc() calls") > > For information about bisection process see: https://goo.gl/tpsmEJ#bisection Interesting, so in fact syzkaller has shown that the aforementioned patch does its job well and has spotted a call path by which a single userland setsockopt() can request more than 2 GB allocation in the kernel. Most likely that's in fact what needs to be addressed. FWIW the call trace at the URL above is: Call Trace: kvmalloc include/linux/mm.h:806 [inline] kvmalloc_array include/linux/mm.h:824 [inline] kvcalloc include/linux/mm.h:829 [inline] xdp_umem_pin_pages net/xdp/xdp_umem.c:102 [inline] xdp_umem_reg net/xdp/xdp_umem.c:219 [inline] xdp_umem_create+0x6a5/0xf00 net/xdp/xdp_umem.c:252 xsk_setsockopt+0x604/0x790 net/xdp/xsk.c:1068 __sys_setsockopt+0x1fd/0x4e0 net/socket.c:2176 __do_sys_setsockopt net/socket.c:2187 [inline] __se_sys_setsockopt net/socket.c:2184 [inline] __x64_sys_setsockopt+0xb5/0x150 net/socket.c:2184 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae and the meaningful part of the repro is: syscall(__NR_mmap, 0x1ffff000ul, 0x1000ul, 0ul, 0x32ul, -1, 0ul); syscall(__NR_mmap, 0x20000000ul, 0x1000000ul, 7ul, 0x32ul, -1, 0ul); syscall(__NR_mmap, 0x21000000ul, 0x1000ul, 0ul, 0x32ul, -1, 0ul); intptr_t res = 0; res = syscall(__NR_socket, 0x2cul, 3ul, 0); if (res != -1) r[0] = res; *(uint64_t*)0x20000080 = 0; *(uint64_t*)0x20000088 = 0xfff02000000; *(uint32_t*)0x20000090 = 0x800; *(uint32_t*)0x20000094 = 0; *(uint32_t*)0x20000098 = 0; syscall(__NR_setsockopt, r[0], 0x11b, 4, 0x20000080ul, 0x20ul); Willy