------------[ cut here ]------------ WARNING: CPU: 1 PID: 25023 at net/ipv4/tcp_input.c:2573 tcp_cwnd_reduction+0x321/0x380 net/ipv4/tcp_input.c:2573 Modules linked in: CPU: 1 PID: 25023 Comm: syz-executor.4 Not tainted 5.14.0-rc5-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:2573 Code: 40 09 00 00 48 83 c4 18 5b 5d 41 5c 41 5d 41 5e 41 5f e9 12 42 d7 f9 e8 0d 42 d7 f9 41 39 ec 41 0f 4e ec eb 89 e8 ff 41 d7 f9 <0f> 0b eb d6 e8 f6 7b 1d fa e9 38 fd ff ff e8 ec 7b 1d fa e9 20 fe RSP: 0018:ffffc900189376d0 EFLAGS: 00010212 RAX: 000000000001ca76 RBX: ffff88803526af00 RCX: ffffc90012596000 RDX: 0000000000040000 RSI: ffffffff879e65c1 RDI: 0000000000000003 RBP: 0000000000000002 R08: 0000000000000000 R09: 0000000000000000 R10: ffffffff879e6318 R11: 0000000000000000 R12: 0000000000000002 R13: 0000000000000000 R14: 0000000000000004 R15: ffff88803526af00 FS: 00007f687511b700(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000540198 CR3: 000000007b87f000 CR4: 00000000001506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: tcp_cong_control net/ipv4/tcp_input.c:3446 [inline] tcp_ack+0x415b/0x59e0 net/ipv4/tcp_input.c:3850 tcp_rcv_established+0x5d7/0x2130 net/ipv4/tcp_input.c:5887 tcp_v4_do_rcv+0x5d4/0x880 net/ipv4/tcp_ipv4.c:1694 sk_backlog_rcv include/net/sock.h:1023 [inline] __release_sock+0x134/0x3b0 net/core/sock.c:2655 __sk_flush_backlog+0x22/0x30 net/core/sock.c:2675 sk_flush_backlog include/net/sock.h:1110 [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:703 [inline] sock_sendmsg+0xcf/0x120 net/socket.c:723 __sys_sendto+0x21c/0x320 net/socket.c:2019 __do_sys_sendto net/socket.c:2031 [inline] __se_sys_sendto net/socket.c:2027 [inline] __x64_sys_sendto+0xdd/0x1b0 net/socket.c:2027 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: 0033:0x4665e9 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:00007f687511b188 EFLAGS: 00000246 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 000000000056bf80 RCX: 00000000004665e9 RDX: 00000000fffffd46 RSI: 0000000020000240 RDI: 0000000000000003 RBP: 00000000004bfcc4 R08: 0000000000000000 R09: 00000000000001f4 R10: 00000000000081f4 R11: 0000000000000246 R12: 000000000056bf80 R13: 0000000000a9fb1f R14: 00007f687511b300 R15: 0000000000022000 ---------------- Code disassembly (best guess), 2 bytes skipped: 0: 00 00 add %al,(%rax) 2: 48 83 c4 18 add $0x18,%rsp 6: 5b pop %rbx 7: 5d pop %rbp 8: 41 5c pop %r12 a: 41 5d pop %r13 c: 41 5e pop %r14 e: 41 5f pop %r15 10: e9 12 42 d7 f9 jmpq 0xf9d74227 15: e8 0d 42 d7 f9 callq 0xf9d74227 1a: 41 39 ec cmp %ebp,%r12d 1d: 41 0f 4e ec cmovle %r12d,%ebp 21: eb 89 jmp 0xffffffac 23: e8 ff 41 d7 f9 callq 0xf9d74227 28: 0f 0b ud2 <-- trapping instruction 2a: eb d6 jmp 0x2 2c: e8 f6 7b 1d fa callq 0xfa1d7c27 31: e9 38 fd ff ff jmpq 0xfffffd6e 36: e8 ec 7b 1d fa callq 0xfa1d7c27 3b: e9 .byte 0xe9 3c: 20 fe and %bh,%dh