------------[ cut here ]------------ WARNING: CPU: 1 PID: 17653 at net/ipv4/tcp_input.c:2573 tcp_cwnd_reduction+0x329/0x390 net/ipv4/tcp_input.c:2573 Modules linked in: CPU: 1 PID: 17653 Comm: syz-executor.3 Not tainted 5.12.0-rc4-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:tcp_cwnd_reduction+0x329/0x390 net/ipv4/tcp_input.c:2573 Code: 38 09 00 00 48 83 c4 18 5b 5d 41 5c 41 5d 41 5e 41 5f e9 ba 17 f5 f9 e8 b5 17 f5 f9 44 39 e5 41 0f 4f ec eb 81 e8 a7 17 f5 f9 <0f> 0b eb d6 e8 de c1 38 fa e9 33 fd ff ff e8 d4 c1 38 fa e9 1c fe RSP: 0018:ffffc900028376b8 EFLAGS: 00010216 RAX: 0000000000017b0b RBX: ffff88802b6cbac0 RCX: ffffc9000f202000 RDX: 0000000000040000 RSI: ffffffff877ed9c9 RDI: 0000000000000003 RBP: ffffc900028378b8 R08: 0000000000000000 R09: 0000000000000000 R10: ffffffff877ed71b R11: 0000000000000000 R12: 0000000000000002 R13: 0000000000000000 R14: 0000000000000004 R15: ffff88802b6cbac0 FS: 0000000000000000(0000) GS:ffff8880b9c00000(0063) knlGS:00000000f54f9b40 CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033 CR2: 0000000008171088 CR3: 000000006602a000 CR4: 00000000001506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: tcp_cong_control net/ipv4/tcp_input.c:3439 [inline] tcp_ack+0x40ac/0x5970 net/ipv4/tcp_input.c:3843 tcp_rcv_established+0x56b/0x1eb0 net/ipv4/tcp_input.c:5872 tcp_v4_do_rcv+0x5d1/0x870 net/ipv4/tcp_ipv4.c:1679 sk_backlog_rcv include/net/sock.h:1016 [inline] __release_sock+0x134/0x3b0 net/core/sock.c:2556 __sk_flush_backlog+0x22/0x30 net/core/sock.c:2576 sk_flush_backlog include/net/sock.h:1103 [inline] tcp_sendmsg_locked+0x27e6/0x2e40 net/ipv4/tcp.c:1304 tcp_sendmsg+0x2b/0x40 net/ipv4/tcp.c:1457 inet_sendmsg+0x99/0xe0 net/ipv4/af_inet.c:821 sock_sendmsg_nosec net/socket.c:654 [inline] sock_sendmsg+0xcf/0x120 net/socket.c:674 __sys_sendto+0x21c/0x320 net/socket.c:1977 __do_sys_sendto net/socket.c:1989 [inline] __se_sys_sendto net/socket.c:1985 [inline] __ia32_sys_sendto+0xdb/0x1b0 net/socket.c:1985 do_syscall_32_irqs_on arch/x86/entry/common.c:77 [inline] __do_fast_syscall_32+0x56/0x90 arch/x86/entry/common.c:140 do_fast_syscall_32+0x2f/0x70 arch/x86/entry/common.c:165 entry_SYSENTER_compat_after_hwframe+0x4d/0x5c RIP: 0023:0xf7eff549 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:00000000f54f95fc EFLAGS: 00000296 ORIG_RAX: 0000000000000171 RAX: ffffffffffffffda RBX: 0000000000000003 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