From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756050AbeEIFjE (ORCPT ); Wed, 9 May 2018 01:39:04 -0400 Received: from mail-pf0-f196.google.com ([209.85.192.196]:32983 "EHLO mail-pf0-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752478AbeEIFjA (ORCPT ); Wed, 9 May 2018 01:39:00 -0400 X-Google-Smtp-Source: AB8JxZqHIG7dqgMuWvCLtgmzB0AQf2BbxxGPuvtaWCwE2j9GlmDpa4toQNn455KH9e7XAC6hl/l3+w== Date: Tue, 8 May 2018 22:40:54 -0700 From: Eric Biggers To: Dmitry Vyukov Cc: dccp@vger.kernel.org, Gerrit Renker , syzbot , David Miller , "Gustavo A . R . Silva" , LKML , netdev , syzkaller-bugs Subject: Re: BUG: please report to dccp@vger.kernel.org => prev = 0, last = 0 at net/dccp/ccids/lib/packet_history.c:LINE/tfrc_rx_his Message-ID: <20180509054054.GF711@sol.localdomain> References: <000000000000fedad9056b7f07ce@google.com> <20180509050509.GE711@sol.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.9.5 (2018-04-13) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, May 09, 2018 at 07:23:41AM +0200, 'Dmitry Vyukov' via syzkaller-bugs wrote: > On Wed, May 9, 2018 at 7:05 AM, Eric Biggers wrote: > > On Sat, May 05, 2018 at 05:57:02PM -0700, syzbot wrote: > >> Hello, > >> > >> syzbot found the following crash on: > >> > >> HEAD commit: c1c07416cdd4 Merge tag 'kbuild-fixes-v4.17' of git://git.k.. > >> git tree: upstream > >> console output: https://syzkaller.appspot.com/x/log.txt?x=13d5de47800000 > >> kernel config: https://syzkaller.appspot.com/x/.config?x=5a1dc06635c10d27 > >> dashboard link: https://syzkaller.appspot.com/bug?extid=99858724c0ba555a12ea > >> compiler: gcc (GCC) 8.0.1 20180413 (experimental) > >> syzkaller repro:https://syzkaller.appspot.com/x/repro.syz?x=170afde7800000 > >> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=141b4be7800000 > >> > >> IMPORTANT: if you fix the bug, please add the following tag to the commit: > >> Reported-by: syzbot+99858724c0ba555a12ea@syzkaller.appspotmail.com > >> > >> random: sshd: uninitialized urandom read (32 bytes read) > >> random: sshd: uninitialized urandom read (32 bytes read) > >> random: sshd: uninitialized urandom read (32 bytes read) > >> random: sshd: uninitialized urandom read (32 bytes read) > >> BUG: please report to dccp@vger.kernel.org => prev = 0, last = 0 at > >> net/dccp/ccids/lib/packet_history.c:425/tfrc_rx_hist_sample_rtt() > >> CPU: 0 PID: 4495 Comm: syz-executor551 Not tainted 4.17.0-rc3+ #34 > >> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS > >> Google 01/01/2011 > >> Call Trace: > >> > >> __dump_stack lib/dump_stack.c:77 [inline] > >> dump_stack+0x1b9/0x294 lib/dump_stack.c:113 > >> tfrc_rx_hist_sample_rtt.cold.3+0x54/0x5c > >> net/dccp/ccids/lib/packet_history.c:422 > >> ccid3_hc_rx_packet_recv+0x5c8/0xed0 net/dccp/ccids/ccid3.c:765 > >> ccid_hc_rx_packet_recv net/dccp/ccid.h:185 [inline] > >> dccp_deliver_input_to_ccids+0xf0/0x280 net/dccp/input.c:180 > >> dccp_rcv_established+0x87/0xb0 net/dccp/input.c:378 > >> dccp_v4_do_rcv+0x153/0x180 net/dccp/ipv4.c:654 > >> sk_backlog_rcv include/net/sock.h:909 [inline] > >> __sk_receive_skb+0x3a2/0xd60 net/core/sock.c:513 > >> dccp_v4_rcv+0x10e5/0x1f3f net/dccp/ipv4.c:875 > >> ip_local_deliver_finish+0x2e3/0xd80 net/ipv4/ip_input.c:215 > >> NF_HOOK include/linux/netfilter.h:288 [inline] > >> ip_local_deliver+0x1e1/0x720 net/ipv4/ip_input.c:256 > >> dst_input include/net/dst.h:450 [inline] > >> ip_rcv_finish+0x81b/0x2200 net/ipv4/ip_input.c:396 > >> NF_HOOK include/linux/netfilter.h:288 [inline] > >> ip_rcv+0xb70/0x143d net/ipv4/ip_input.c:492 > >> __netif_receive_skb_core+0x26f5/0x3630 net/core/dev.c:4592 > >> __netif_receive_skb+0x2c/0x1e0 net/core/dev.c:4657 > >> process_backlog+0x219/0x760 net/core/dev.c:5337 > >> napi_poll net/core/dev.c:5735 [inline] > >> net_rx_action+0x7b7/0x1930 net/core/dev.c:5801 > >> __do_softirq+0x2e0/0xaf5 kernel/softirq.c:285 > >> do_softirq_own_stack+0x2a/0x40 arch/x86/entry/entry_64.S:1046 > >> > >> do_softirq.part.17+0x14d/0x190 kernel/softirq.c:329 > >> do_softirq arch/x86/include/asm/preempt.h:23 [inline] > >> __local_bh_enable_ip+0x1ec/0x230 kernel/softirq.c:182 > >> local_bh_enable include/linux/bottom_half.h:32 [inline] > >> rcu_read_unlock_bh include/linux/rcupdate.h:728 [inline] > >> ip_finish_output2+0xab2/0x1840 net/ipv4/ip_output.c:231 > >> ip_finish_output+0x828/0xf80 net/ipv4/ip_output.c:317 > >> NF_HOOK_COND include/linux/netfilter.h:277 [inline] > >> ip_output+0x21b/0x850 net/ipv4/ip_output.c:405 > >> dst_output include/net/dst.h:444 [inline] > >> ip_local_out+0xc5/0x1b0 net/ipv4/ip_output.c:124 > >> ip_queue_xmit+0x9d7/0x1f70 net/ipv4/ip_output.c:504 > >> dccp_transmit_skb+0x999/0x12e0 net/dccp/output.c:142 > >> dccp_xmit_packet+0x250/0x790 net/dccp/output.c:281 > >> dccp_write_xmit+0x190/0x1f0 net/dccp/output.c:363 > >> dccp_sendmsg+0x8c7/0x1020 net/dccp/proto.c:818 > >> inet_sendmsg+0x19f/0x690 net/ipv4/af_inet.c:798 > >> sock_sendmsg_nosec net/socket.c:629 [inline] > >> sock_sendmsg+0xd5/0x120 net/socket.c:639 > >> ___sys_sendmsg+0x525/0x940 net/socket.c:2117 > >> __sys_sendmmsg+0x240/0x6f0 net/socket.c:2212 > >> __do_sys_sendmmsg net/socket.c:2241 [inline] > >> __se_sys_sendmmsg net/socket.c:2238 [inline] > >> __x64_sys_sendmmsg+0x9d/0x100 net/socket.c:2238 > >> do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:287 > >> entry_SYSCALL_64_after_hwframe+0x49/0xbe > >> RIP: 0033:0x445d09 > >> RSP: 002b:00007f3c7eff5d88 EFLAGS: 00000293 ORIG_RAX: 0000000000000133 > >> RAX: ffffffffffffffda RBX: 00000000006dac40 RCX: 0000000000445d09 > >> RDX: 0000000000000001 RSI: 000000 > >> > >> > >> --- > >> This bug is generated by a bot. It may contain errors. > >> See https://goo.gl/tpsmEJ for more information about syzbot. > >> syzbot engineers can be reached at syzkaller@googlegroups.com. > >> > >> syzbot will keep track of this bug report. > >> If you forgot to add the Reported-by tag, once the fix for this bug is > >> merged > >> into any tree, please reply to this email with: > >> #syz fix: exact-commit-title > >> If you want to test a patch for this bug, please reply with: > >> #syz test: git://repo/address.git branch > >> and provide the patch inline or as an attachment. > >> To mark this as a duplicate of another syzbot report, please reply with: > >> #syz dup: exact-subject-of-another-report > > > > There's already a bug report with this title, this one just had a few characters > > truncated from the end. Dmitry, is that intentional? The other one is > > https://groups.google.com/forum/#!msg/syzkaller-bugs/u5nq3PdPkIc/bBFjKHXPAgAJ: > > > > #syz dup: BUG: please report to dc...@vger.kernel.org => prev = 0, last = 0 at net/dccp/ccids/lib/packet_history.c:LINE/tfrc_rx_hist_sample_rtt() > > I think this happened when we started truncating kernel crash titles > to 120 columns, so it's intentional. > However, the dup command did not pass. It's hard to understand who > received what today, but this suggests that somebody altered email in > the command to dc...@vger.kernel.org: > https://groups.google.com/forum/message/raw?msg=syzkaller-bugs/GMndq4-h7BI/VIz4aBEOAwAJ > We can also mark the old one as invalid. > Ah, that was my fault -- I must have copied the bug title from the syzkaller-bugs Google Groups page, which had mangled the email address in the bug title. The actual title was: #syz dup: BUG: please report to dccp@vger.kernel.org => prev = 0, last = 0 at net/dccp/ccids/lib/packet_history.c:LINE/tfrc_rx_hist_sample_rtt()