BUG: please report to dccp@vger.kernel.org => prev = 0, last = 0 at net/dccp/ccids/lib/packet_history.c:414/tfrc_rx_hist_sample_rtt() CPU: 1 PID: 19 Comm: ksoftirqd/1 Not tainted 5.13.0-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:79 [inline] dump_stack+0x141/0x1d7 lib/dump_stack.c:120 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+0xe1/0x260 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:1020 [inline] __sk_receive_skb+0x29d/0x830 net/core/sock.c:509 dccp_v4_rcv+0xea5/0x19d0 net/dccp/ipv4.c:890 ip_protocol_deliver_rcu+0x5c/0xa20 net/ipv4/ip_input.c:204 ip_local_deliver_finish+0x20a/0x370 net/ipv4/ip_input.c:231 NF_HOOK include/linux/netfilter.h:307 [inline] NF_HOOK include/linux/netfilter.h:301 [inline] ip_local_deliver+0x1b3/0x200 net/ipv4/ip_input.c:252 dst_input include/net/dst.h:458 [inline] ip_rcv_finish+0x1da/0x2f0 net/ipv4/ip_input.c:429 NF_HOOK include/linux/netfilter.h:307 [inline] NF_HOOK include/linux/netfilter.h:301 [inline] ip_rcv+0xaa/0xd0 net/ipv4/ip_input.c:540 __netif_receive_skb_one_core+0x114/0x180 net/core/dev.c:5459 __netif_receive_skb+0x27/0x1c0 net/core/dev.c:5573 process_backlog+0x232/0x6c0 net/core/dev.c:6437 __napi_poll+0xaf/0x440 net/core/dev.c:6992 napi_poll net/core/dev.c:7059 [inline] net_rx_action+0x801/0xb40 net/core/dev.c:7146 __do_softirq+0x29b/0x9f6 kernel/softirq.c:559 run_ksoftirqd kernel/softirq.c:921 [inline] run_ksoftirqd+0x2d/0x60 kernel/softirq.c:913 smpboot_thread_fn+0x655/0x9e0 kernel/smpboot.c:165 kthread+0x3b1/0x4a0 kernel/kthread.c:313 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294