BUG: please report to dccp@vger.kernel.org => prev = 0, last = 0 at net/dccp/ccids/lib/packet_history.c:417/tfrc_rx_hist_sample_rtt() CPU: 0 UID: 0 PID: 5326 Comm: syz.0.0 Not tainted 6.14.0-rc2-syzkaller-00228-g04f41cbf03ec #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120 tfrc_rx_hist_sample_rtt+0x397/0x4b0 net/dccp/ccids/lib/packet_history.c:414 ccid3_hc_rx_packet_recv+0x69d/0xe60 net/dccp/ccids/ccid3.c:760 ccid_hc_rx_packet_recv net/dccp/ccid.h:182 [inline] dccp_deliver_input_to_ccids net/dccp/input.c:176 [inline] dccp_rcv_established+0x1bb/0x320 net/dccp/input.c:374 dccp_v4_do_rcv+0xff/0x1f0 net/dccp/ipv4.c:681 sk_backlog_rcv include/net/sock.h:1122 [inline] __sk_receive_skb+0x82b/0x8b0 net/core/sock.c:575 ip_protocol_deliver_rcu+0x2e9/0x440 net/ipv4/ip_input.c:205 ip_local_deliver_finish+0x341/0x5f0 net/ipv4/ip_input.c:233 NF_HOOK+0x3a4/0x450 include/linux/netfilter.h:314 NF_HOOK+0x3a4/0x450 include/linux/netfilter.h:314 __netif_receive_skb_one_core net/core/dev.c:5828 [inline] __netif_receive_skb+0x2bf/0x650 net/core/dev.c:5941 process_backlog+0x662/0x15b0 net/core/dev.c:6289 __napi_poll+0xcb/0x490 net/core/dev.c:7106 napi_poll net/core/dev.c:7175 [inline] net_rx_action+0x89b/0x1240 net/core/dev.c:7297 handle_softirqs+0x2d4/0x9b0 kernel/softirq.c:561 do_softirq+0x11b/0x1e0 kernel/softirq.c:462 __local_bh_enable_ip+0x1bb/0x200 kernel/softirq.c:389 local_bh_enable include/linux/bottom_half.h:33 [inline] rcu_read_unlock_bh include/linux/rcupdate.h:919 [inline] __dev_queue_xmit+0x1775/0x3f50 net/core/dev.c:4611 dev_queue_xmit include/linux/netdevice.h:3311 [inline] neigh_hh_output include/net/neighbour.h:523 [inline] neigh_output include/net/neighbour.h:537 [inline] ip_finish_output2+0xcd3/0x12e0 net/ipv4/ip_output.c:236 ip_local_out net/ipv4/ip_output.c:130 [inline] __ip_queue_xmit+0x103f/0x1960 net/ipv4/ip_output.c:528 dccp_transmit_skb+0xf37/0x16d0 net/dccp/output.c:138 dccp_xmit_packet+0x376/0x610 net/dccp/output.c:281 dccp_write_xmit+0x138/0x220 net/dccp/output.c:366 dccp_sendmsg+0x76f/0xb90 net/dccp/proto.c:801 sock_sendmsg_nosec net/socket.c:718 [inline] __sock_sendmsg+0x1a6/0x270 net/socket.c:733 __sys_sendto+0x363/0x4c0 net/socket.c:2187 __do_sys_sendto net/socket.c:2194 [inline] __se_sys_sendto net/socket.c:2190 [inline] __x64_sys_sendto+0xde/0x100 net/socket.c:2190 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f652d18cde9 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 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f652dfb2038 EFLAGS: 00000246 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 00007f652d3a5fa0 RCX: 00007f652d18cde9 RDX: 0000000000000006 RSI: 0000400000000140 RDI: 0000000000000005 RBP: 00007f652d20e2a0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000004000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f652d3a5fa0 R15: 00007ffd1f3a0648