ccid3_first_li: No RTT estimate available, using fallback RTT
ccid3_first_li: X_recv==0
BUG: stored value of X_recv is zero at net/dccp/ccids/ccid3.c:691/ccid3_first_li()
CPU: 1 PID: 11737 Comm: syz-fuzzer Not tainted 5.14.0-rc5-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
 ccid3_first_li.cold+0x67/0x17a net/dccp/ccids/ccid3.c:691
 tfrc_lh_interval_add+0x640/0x8e0 net/dccp/ccids/lib/loss_interval.c:157
 tfrc_rx_handle_loss+0x41b/0x1fa0 net/dccp/ccids/lib/packet_history.c:328
 ccid3_hc_rx_packet_recv+0x385/0xe90 net/dccp/ccids/ccid3.c:744
 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:1023 [inline]
 __sk_receive_skb+0x29d/0x830 net/core/sock.c:527
 dccp_v4_rcv+0xea5/0x19d0 net/dccp/ipv4.c:890
 ip_protocol_deliver_rcu+0xa7/0xa20 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:5498
 __netif_receive_skb+0x24/0x1b0 net/core/dev.c:5612
 process_backlog+0x2a5/0x6c0 net/core/dev.c:6492
 __napi_poll+0xaf/0x440 net/core/dev.c:7047
 napi_poll net/core/dev.c:7114 [inline]
 net_rx_action+0x801/0xb40 net/core/dev.c:7201
 __do_softirq+0x29b/0x9c2 kernel/softirq.c:558
 invoke_softirq kernel/softirq.c:432 [inline]
 __irq_exit_rcu+0x16e/0x1c0 kernel/softirq.c:636
 irq_exit_rcu+0x5/0x20 kernel/softirq.c:648
 sysvec_apic_timer_interrupt+0x45/0xc0 arch/x86/kernel/apic/apic.c:1100
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638
RIP: 0033:0x43132b
Code: 48 8b 4c 24 40 48 8b 54 24 38 48 8b 5c 24 30 eb 9e 90 48 89 d3 48 c1 ea 03 48 83 e3 07 48 89 ce 48 89 d9 bf 01 00 00 00 d3 e7 <90> 48 03 50 50 0f b6 1a 40 84 df 74 19 48 8b 44 24 58 48 8b 4c 24
RSP: 002b:000000c00ca55f60 EFLAGS: 00000202
RAX: 00007ff3437d4f70 RBX: 0000000000000001 RCX: 0000000000000001
RDX: 0000000000000014 RSI: 000000c013793420 RDI: 0000000000000002
RBP: 000000c00ca55fa8 R08: 000000000000000b R09: ffffffffffffffff
R10: 00007ff343dc41c0 R11: 000000c000020f58 R12: 000000c00181c6f0
R13: 000000c000020f48 R14: 000000000094d49c R15: 0000000000000000
----------------
Code disassembly (best guess):
   0:	48 8b 4c 24 40       	mov    0x40(%rsp),%rcx
   5:	48 8b 54 24 38       	mov    0x38(%rsp),%rdx
   a:	48 8b 5c 24 30       	mov    0x30(%rsp),%rbx
   f:	eb 9e                	jmp    0xffffffaf
  11:	90                   	nop
  12:	48 89 d3             	mov    %rdx,%rbx
  15:	48 c1 ea 03          	shr    $0x3,%rdx
  19:	48 83 e3 07          	and    $0x7,%rbx
  1d:	48 89 ce             	mov    %rcx,%rsi
  20:	48 89 d9             	mov    %rbx,%rcx
  23:	bf 01 00 00 00       	mov    $0x1,%edi
  28:	d3 e7                	shl    %cl,%edi
  2a:	90                   	nop <-- trapping instruction
  2b:	48 03 50 50          	add    0x50(%rax),%rdx
  2f:	0f b6 1a             	movzbl (%rdx),%ebx
  32:	40 84 df             	test   %bl,%dil
  35:	74 19                	je     0x50
  37:	48 8b 44 24 58       	mov    0x58(%rsp),%rax
  3c:	48                   	rex.W
  3d:	8b                   	.byte 0x8b
  3e:	4c                   	rex.WR
  3f:	24                   	.byte 0x24