------------[ cut here ]------------ WARNING: CPU: 0 PID: 4843 at net/ipv4/tcp_input.c:2605 tcp_cwnd_reduction+0x321/0x380 net/ipv4/tcp_input.c:2605 Modules linked in: CPU: 0 PID: 4843 Comm: syz-executor.1 Not tainted 5.15.0-rc2-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:2605 Code: 48 09 00 00 48 83 c4 18 5b 5d 41 5c 41 5d 41 5e 41 5f e9 42 58 d1 f9 e8 3d 58 d1 f9 41 39 ec 41 0f 4e ec eb 89 e8 2f 58 d1 f9 <0f> 0b eb d6 e8 66 a7 18 fa e9 38 fd ff ff e8 5c a7 18 fa e9 20 fe RSP: 0018:ffffc900174476d0 EFLAGS: 00010212 RAX: 00000000000154fe RBX: ffff88807aa5d240 RCX: ffffc900068c3000 RDX: 0000000000040000 RSI: ffffffff87a4b341 RDI: 0000000000000003 RBP: 0000000000000002 R08: 0000000000000000 R09: 0000000000000000 R10: ffffffff87a4b098 R11: 0000000000000000 R12: 0000000000000002 R13: 0000000000000000 R14: 0000000000000004 R15: ffff88807aa5d240 FS: 00007f28a18ca700(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055c12c0f0548 CR3: 00000000774f8000 CR4: 00000000001526e0 Call Trace: tcp_cong_control net/ipv4/tcp_input.c:3478 [inline] tcp_ack+0x415b/0x59e0 net/ipv4/tcp_input.c:3882 tcp_rcv_established+0x5d7/0x2130 net/ipv4/tcp_input.c:5919 tcp_v4_do_rcv+0x5d4/0x880 net/ipv4/tcp_ipv4.c:1694 sk_backlog_rcv include/net/sock.h:1024 [inline] __release_sock+0x134/0x3b0 net/core/sock.c:2668 __sk_flush_backlog+0x22/0x30 net/core/sock.c:2688 sk_flush_backlog include/net/sock.h:1111 [inline] tcp_sendmsg_locked+0x2817/0x2f10 net/ipv4/tcp.c:1305 tcp_sendmsg+0x2b/0x40 net/ipv4/tcp.c:1461 inet_sendmsg+0x99/0xe0 net/ipv4/af_inet.c:821 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: 0033:0x7f28a4353709 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:00007f28a18ca188 EFLAGS: 00000246 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 00007f28a4457f60 RCX: 00007f28a4353709 RDX: 00000000fffffd46 RSI: 0000000020000240 RDI: 0000000000000003 RBP: 00007f28a43adcb4 R08: 0000000000000000 R09: 00000000000001f4 R10: 00000000000081f4 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f28a498bb2f R14: 00007f28a18ca300 R15: 0000000000022000