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=-5.2 required=3.0 tests=FROM_EXCESS_BASE64, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,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 8ADB0C3A59D for ; Tue, 20 Aug 2019 09:17:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 61D89216F4 for ; Tue, 20 Aug 2019 09:17:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729461AbfHTJRz (ORCPT ); Tue, 20 Aug 2019 05:17:55 -0400 Received: from mga03.intel.com ([134.134.136.65]:52917 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728414AbfHTJRz (ORCPT ); Tue, 20 Aug 2019 05:17:55 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga007.jf.intel.com ([10.7.209.58]) by orsmga103.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 20 Aug 2019 02:17:53 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.64,408,1559545200"; d="scan'208";a="169026483" Received: from arappl-mobl2.ger.corp.intel.com (HELO btopel-mobl.ger.intel.com) ([10.252.53.140]) by orsmga007.jf.intel.com with ESMTP; 20 Aug 2019 02:17:47 -0700 Subject: Re: general protection fault in xsk_poll To: Hillf Danton , syzbot Cc: ast@kernel.org, bpf@vger.kernel.org, daniel@iogearbox.net, davem@davemloft.net, hawk@kernel.org, jakub.kicinski@netronome.com, john.fastabend@gmail.com, jonathan.lemon@gmail.com, kafai@fb.com, linux-kernel@vger.kernel.org, magnus.karlsson@intel.com, netdev@vger.kernel.org, songliubraving@fb.com, syzkaller-bugs@googlegroups.com, xdp-newbies@vger.kernel.org, yhs@fb.com References: <20190820033154.9112-1-hdanton@sina.com> From: =?UTF-8?B?QmrDtnJuIFTDtnBlbA==?= Message-ID: <8a10ea50-fe61-55fd-0be4-5dff56d7effd@intel.com> Date: Tue, 20 Aug 2019 11:17:46 +0200 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: <20190820033154.9112-1-hdanton@sina.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2019-08-20 05:31, Hillf Danton wrote: > > On Mon, 19 Aug 2019 18:18:06 -0700 >> Hello, >> >> syzbot found the following crash on: >> >> HEAD commit: da657043 Add linux-next specific files for 20190819 >> git tree: linux-next >> console output: https://syzkaller.appspot.com/x/log.txt?x=16af124c600000 >> kernel config: https://syzkaller.appspot.com/x/.config?x=739a9b3ab3d8c770 >> dashboard link: https://syzkaller.appspot.com/bug?extid=c82697e3043781e08802 >> compiler: gcc (GCC) 9.0.0 20181231 (experimental) >> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=109e1922600000 >> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1445bf02600000 >> >> The bug was bisected to: >> >> commit 77cd0d7b3f257fd0e3096b4fdcff1a7d38e99e10 >> Author: Magnus Karlsson >> Date: Wed Aug 14 07:27:17 2019 +0000 >> >> xsk: add support for need_wakeup flag in AF_XDP rings >> >> bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=15e1ea4c600000 >> final crash: https://syzkaller.appspot.com/x/report.txt?x=17e1ea4c600000 >> console output: https://syzkaller.appspot.com/x/log.txt?x=13e1ea4c600000 >> >> IMPORTANT: if you fix the bug, please add the following tag to the commit: >> Reported-by: syzbot+c82697e3043781e08802@syzkaller.appspotmail.com >> Fixes: 77cd0d7b3f25 ("xsk: add support for need_wakeup flag in AF_XDP rings") >> >> kasan: CONFIG_KASAN_INLINE enabled >> kasan: GPF could be caused by NULL-ptr deref or user memory access >> general protection fault: 0000 [#1] PREEMPT SMP KASAN >> CPU: 1 PID: 7959 Comm: syz-executor611 Not tainted 5.3.0-rc5-next-20190819 #68 >> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS >> Google 01/01/2011 >> RIP: 0010:xsk_poll+0x95/0x540 net/xdp/xsk.c:386 >> Code: 80 3c 02 00 0f 85 70 04 00 00 4c 8b a3 88 04 00 00 48 b8 00 00 00 00 >> 00 fc ff df 49 8d bc 24 96 00 00 00 48 89 fa 48 c1 ea 03 <0f> b6 04 02 48 >> 89 fa 83 e2 07 38 d0 7f 08 84 c0 0f 85 bf 03 00 00 >> RSP: 0018:ffff8880926f7850 EFLAGS: 00010207 >> RAX: dffffc0000000000 RBX: ffff88809a141700 RCX: ffffffff859b07aa >> RDX: 0000000000000012 RSI: ffffffff859b07c4 RDI: 0000000000000096 >> RBP: ffff8880926f7880 R08: ffff88809698a580 R09: ffffed1013428329 >> R10: ffffed1013428328 R11: ffff88809a141947 R12: 0000000000000000 >> R13: 0000000000000304 R14: ffff888095d4d840 R15: ffff888092bdd020 >> FS: 0000555557529880(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000 >> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 >> CR2: 0000000020000280 CR3: 0000000098281000 CR4: 00000000001406e0 >> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 >> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 >> Call Trace: >> sock_poll+0x15e/0x480 net/socket.c:1256 >> vfs_poll include/linux/poll.h:90 [inline] >> do_pollfd fs/select.c:859 [inline] >> do_poll fs/select.c:907 [inline] >> do_sys_poll+0x7c2/0xde0 fs/select.c:1001 >> __do_sys_ppoll fs/select.c:1101 [inline] >> __se_sys_ppoll fs/select.c:1081 [inline] >> __x64_sys_ppoll+0x259/0x310 fs/select.c:1081 >> do_syscall_64+0xfa/0x760 arch/x86/entry/common.c:290 >> entry_SYSCALL_64_after_hwframe+0x49/0xbe >> RIP: 0033:0x440159 >> Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 48 89 f8 48 89 f7 >> 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff >> ff 0f 83 fb 13 fc ff c3 66 2e 0f 1f 84 00 00 00 00 >> RSP: 002b:00007ffd9fbd16e8 EFLAGS: 00000246 ORIG_RAX: 000000000000010f >> RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 0000000000440159 >> RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000020000280 >> RBP: 00000000006ca018 R08: 0000000000000000 R09: 00000000004002c8 >> R10: 0000000000000000 R11: 0000000000000246 R12: 00000000004019e0 >> R13: 0000000000401a70 R14: 0000000000000000 R15: 0000000000000000 >> Modules linked in: >> ---[ end trace da907175426b4065 ]--- > > Add umem check. > > --- a/net/xdp/xsk.c > +++ b/net/xdp/xsk.c > @@ -381,9 +381,9 @@ static unsigned int xsk_poll(struct file > struct sock *sk = sock->sk; > struct xdp_sock *xs = xdp_sk(sk); > struct net_device *dev = xs->dev; > - struct xdp_umem *umem = xs->umem; > + struct xdp_umem *umem = READ_ONCE(xs->umem); > > - if (umem->need_wakeup) > + if (umem && umem->need_wakeup) > dev->netdev_ops->ndo_xsk_wakeup(dev, xs->queue_id, > umem->need_wakeup); > > -- > Thanks! What do you think about making it a bit more generic, like: diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c index ee4428a892fa..08bed5e92af4 100644 --- a/net/xdp/xsk.c +++ b/net/xdp/xsk.c @@ -356,13 +356,20 @@ static int xsk_generic_xmit(struct sock *sk, struct msghdr *m, return err; } +static bool xsk_is_bound(struct xdp_sock *xs) +{ + struct net_device *dev = READ_ONCE(xs->dev); + + return dev && xs->state == XSK_BOUND; +} + static int xsk_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len) { bool need_wait = !(m->msg_flags & MSG_DONTWAIT); struct sock *sk = sock->sk; struct xdp_sock *xs = xdp_sk(sk); - if (unlikely(!xs->dev)) + if (unlikely(!xsk_is_bound(xs))) return -ENXIO; if (unlikely(!(xs->dev->flags & IFF_UP))) return -ENETDOWN; @@ -383,6 +390,9 @@ static unsigned int xsk_poll(struct file *file, struct socket *sock, struct net_device *dev = xs->dev; struct xdp_umem *umem = xs->umem; + if (unlikely(!xsk_is_bound(xs))) + return mask; + if (umem->need_wakeup) dev->netdev_ops->ndo_xsk_wakeup(dev, xs->queue_id, umem->need_wakeup); @@ -417,7 +427,7 @@ static void xsk_unbind_dev(struct xdp_sock *xs) { struct net_device *dev = xs->dev; - if (!dev || xs->state != XSK_BOUND) + if (!xsk_is_bound(xs)) return; xs->state = XSK_UNBOUND;