------------[ cut here ]------------
WARNING: CPU: 0 PID: 10610 at net/ipv4/tcp_input.c:2613 tcp_cwnd_reduction+0x321/0x380 net/ipv4/tcp_input.c:2613
Modules linked in:
CPU: 0 PID: 10610 Comm: syz-executor.4 Not tainted 5.16.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:tcp_cwnd_reduction+0x321/0x380 net/ipv4/tcp_input.c:2613
Code: 80 09 00 00 48 83 c4 18 5b 5d 41 5c 41 5d 41 5e 41 5f e9 12 a7 b9 f9 e8 0d a7 b9 f9 41 39 ec 41 0f 4e ec eb 89 e8 ff a6 b9 f9 <0f> 0b eb d6 e8 16 5f 00 fa e9 38 fd ff ff e8 0c 5f 00 fa e9 20 fe
RSP: 0018:ffffc9000400f6b0 EFLAGS: 00010216
RAX: 0000000000005aad RBX: ffff88807c51ec00 RCX: ffffc900122ec000
RDX: 0000000000040000 RSI: ffffffff87be40e1 RDI: 0000000000000003
RBP: 0000000000000009 R08: 0000000000000000 R09: 0000000000000000
R10: ffffffff87be3e38 R11: 0000000000000000 R12: 0000000000000009
R13: 0000000000000000 R14: 0000000000000004 R15: ffff88807c51ec00
FS:  0000000000000000(0000) GS:ffff8880b9d00000(0063) knlGS:00000000f447fb40
CS:  0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: 000055e1baa3fbd0 CR3: 0000000076d0b000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 tcp_cong_control net/ipv4/tcp_input.c:3485 [inline]
 tcp_ack+0x4160/0x5920 net/ipv4/tcp_input.c:3889
 tcp_rcv_established+0x5d7/0x2130 net/ipv4/tcp_input.c:5936
 tcp_v4_do_rcv+0x600/0x8d0 net/ipv4/tcp_ipv4.c:1716
 sk_backlog_rcv include/net/sock.h:1030 [inline]
 __release_sock+0x134/0x3b0 net/core/sock.c:2768
 __sk_flush_backlog+0x22/0x30 net/core/sock.c:2788
 sk_flush_backlog include/net/sock.h:1117 [inline]
 tcp_sendmsg_locked+0x2989/0x3040 net/ipv4/tcp.c:1277
 tcp_sendmsg+0x2b/0x40 net/ipv4/tcp.c:1440
 inet_sendmsg+0x99/0xe0 net/ipv4/af_inet.c:819
 sock_sendmsg_nosec net/socket.c:704 [inline]
 sock_sendmsg+0xcf/0x120 net/socket.c:724
 __sys_sendto+0x21c/0x320 net/socket.c:2036
 __do_sys_sendto net/socket.c:2048 [inline]
 __se_sys_sendto net/socket.c:2044 [inline]
 __ia32_sys_sendto+0xdb/0x1b0 net/socket.c:2044
 do_syscall_32_irqs_on arch/x86/entry/common.c:112 [inline]
 __do_fast_syscall_32+0x65/0xf0 arch/x86/entry/common.c:178
 do_fast_syscall_32+0x2f/0x70 arch/x86/entry/common.c:203
 entry_SYSENTER_compat_after_hwframe+0x4d/0x5c
RIP: 0023:0xf6e85549
Code: 03 74 c0 01 10 05 03 74 b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00
RSP: 002b:00000000f447f5fc EFLAGS: 00000296 ORIG_RAX: 0000000000000171
RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 0000000020000240
RDX: 00000000fffffd46 RSI: 00000000000081f4 RDI: 0000000000000000
RBP: 00000000000001f4 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>
----------------
Code disassembly (best guess):
   0:	03 74 c0 01          	add    0x1(%rax,%rax,8),%esi
   4:	10 05 03 74 b8 01    	adc    %al,0x1b87403(%rip)        # 0x1b8740d
   a:	10 06                	adc    %al,(%rsi)
   c:	03 74 b4 01          	add    0x1(%rsp,%rsi,4),%esi
  10:	10 07                	adc    %al,(%rdi)
  12:	03 74 b0 01          	add    0x1(%rax,%rsi,4),%esi
  16:	10 08                	adc    %cl,(%rax)
  18:	03 74 d8 01          	add    0x1(%rax,%rbx,8),%esi
  1c:	00 00                	add    %al,(%rax)
  1e:	00 00                	add    %al,(%rax)
  20:	00 51 52             	add    %dl,0x52(%rcx)
  23:	55                   	push   %rbp
  24:	89 e5                	mov    %esp,%ebp
  26:	0f 34                	sysenter
  28:	cd 80                	int    $0x80
* 2a:	5d                   	pop    %rbp <-- trapping instruction
  2b:	5a                   	pop    %rdx
  2c:	59                   	pop    %rcx
  2d:	c3                   	retq
  2e:	90                   	nop
  2f:	90                   	nop
  30:	90                   	nop
  31:	90                   	nop
  32:	8d b4 26 00 00 00 00 	lea    0x0(%rsi,%riz,1),%esi
  39:	8d b4 26 00 00 00 00 	lea    0x0(%rsi,%riz,1),%esi