------------[ cut here ]------------
WARNING: CPU: 3 PID: 16201 at net/ipv4/tcp_input.c:2613 tcp_cwnd_reduction+0x321/0x380 net/ipv4/tcp_input.c:2613
Modules linked in:
CPU: 3 PID: 16201 Comm: syz-executor.1 Not tainted 5.15.0-syzkaller #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-2 04/01/2014
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 b2 c6 d0 f9 e8 ad c6 d0 f9 41 39 ec 41 0f 4e ec eb 89 e8 9f c6 d0 f9 <0f> 0b eb d6 e8 06 e1 16 fa e9 38 fd ff ff e8 fc e0 16 fa e9 20 fe
RSP: 0018:ffffc9000383f6e8 EFLAGS: 00010212
RAX: 000000000002f616 RBX: ffff888023068680 RCX: ffffc90022973000
RDX: 0000000000040000 RSI: ffffffff87a63991 RDI: 0000000000000003
RBP: 0000000000000012 R08: 0000000000000000 R09: 0000000000000000
R10: ffffffff87a636e8 R11: 0000000000000000 R12: 0000000000000012
R13: 0000000000000000 R14: 0000000000000008 R15: ffff888023068680
FS:  00007fddae9b2700(0000) GS:ffff88802cd00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005555567bc708 CR3: 0000000067763000 CR4: 0000000000152ee0
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+0x3fc1/0x5720 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+0x2676/0x2c60 net/ipv4/tcp.c:1276
 tcp_sendmsg+0x2b/0x40 net/ipv4/tcp.c:1422
 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]
 __x64_sys_sendto+0xdd/0x1b0 net/socket.c:2044
 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: 0033:0x7fddb143cae9
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:00007fddae9b2188 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007fddb154ff60 RCX: 00007fddb143cae9
RDX: ffffffffffffffef RSI: 0000000020d7cfcb RDI: 0000000000000005
RBP: 00007fddb1496f25 R08: 0000000000000000 R09: 0000000000000053
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fff1a2a491f R14: 00007fddae9b2300 R15: 0000000000022000
 </TASK>