Hello, syzbot found the following issue on: HEAD commit: e3f30ab28ac8 Merge branch 'pktgen-samples-next' git tree: net-next console output: https://syzkaller.appspot.com/x/log.txt?x=13a18a59300000 kernel config: https://syzkaller.appspot.com/x/.config?x=ef482942966bf763 dashboard link: https://syzkaller.appspot.com/bug?extid=d9bd66f8d352f7eb1955 compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.1 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=12bfe5d5300000 IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+d9bd66f8d352f7eb1955@xxxxxxxxxxxxxxxxxxxxxxxxx BUG: please report to dccp@xxxxxxxxxxxxxxx => prev = 0, last = 0 at net/dccp/ccids/lib/packet_history.c:414/tfrc_rx_hist_sample_rtt() CPU: 1 PID: 13730 Comm: syz-executor.2 Not tainted 5.14.0-rc6-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:105 tfrc_rx_hist_sample_rtt+0x4a5/0x4b0 net/dccp/ccids/lib/packet_history.c:414 ccid3_hc_rx_packet_recv+0x5b8/0xe90 net/dccp/ccids/ccid3.c:760 ccid_hc_rx_packet_recv net/dccp/ccid.h:182 [inline] dccp_deliver_input_to_ccids+0xd9/0x250 net/dccp/input.c:176 dccp_rcv_established net/dccp/input.c:374 [inline] dccp_rcv_established+0x107/0x160 net/dccp/input.c:364 dccp_v4_do_rcv+0x130/0x190 net/dccp/ipv4.c:667 sk_backlog_rcv include/net/sock.h:1024 [inline] __release_sock+0x134/0x3b0 net/core/sock.c:2669 release_sock+0x54/0x1b0 net/core/sock.c:3201 dccp_sendmsg+0x67a/0xc90 net/dccp/proto.c:796 inet_sendmsg+0x99/0xe0 net/ipv4/af_inet.c:821 sock_sendmsg_nosec net/socket.c:704 [inline] sock_sendmsg+0xcf/0x120 net/socket.c:724 ____sys_sendmsg+0x331/0x810 net/socket.c:2403 ___sys_sendmsg+0xf3/0x170 net/socket.c:2457 __sys_sendmmsg+0x195/0x470 net/socket.c:2543 __do_sys_sendmmsg net/socket.c:2572 [inline] __se_sys_sendmmsg net/socket.c:2569 [inline] __x64_sys_sendmmsg+0x99/0x100 net/socket.c:2569 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 RIP: 0033:0x4665e9 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f94cb63e188 EFLAGS: 00000246 ORIG_RAX: 0000000000000133 RAX: ffffffffffffffda RBX: 000000000056c0f0 RCX: 00000000004665e9 RDX: 0000000000000002 RSI: 0000000020000240 RDI: 0000000000000004 RBP: 00000000004bfcc4 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056c0f0 R13: 00007ffd68749c0f R14: 00007f94cb63e300 R15: 0000000000022000 --- This report 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@xxxxxxxxxxxxxxxx. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. syzbot can test patches for this issue, for details see: https://goo.gl/tpsmEJ#testing-patches
