RBP: 00007f4e558f4090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007f4e54be6038 R14: 00007f4e54be5fa0 R15: 00007fff219d8fb8
 </TASK>
Oops: divide error: 0000 [#1] SMP KASAN NOPTI
CPU: 0 UID: 0 PID: 7884 Comm: syz.2.442 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:__tcp_select_window+0x5a8/0x12e0 net/ipv4/tcp_output.c:3333
Code: 45 01 e7 44 89 ff e8 77 16 f0 f7 45 39 f7 0f 8d 11 ff ff ff e8 e9 1b f0 f7 45 89 f4 e9 04 ff ff ff e8 dc 1b f0 f7 44 89 f0 99 <f7> 7c 24 14 41 29 d6 45 89 f4 e9 ec fe ff ff e8 c4 1b f0 f7 48 89
RSP: 0018:ffffc90005e875a0 EFLAGS: 00010293
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff89cccb8d
RDX: 0000000000000000 RSI: ffffffff89cccbf4 RDI: 0000000000000004
RBP: 0000000000000000 R08: 0000000000000004 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000000
R13: ffff88802b876d40 R14: 0000000000000000 R15: 0000000000000000
FS:  00007f4e558f46c0(0000) GS:ffff888124a05000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000000180 CR3: 000000005218b000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 tcp_select_window net/ipv4/tcp_output.c:280 [inline]
 __tcp_transmit_skb+0xcf6/0x44d0 net/ipv4/tcp_output.c:1565
 tcp_transmit_skb net/ipv4/tcp_output.c:1646 [inline]
 tcp_send_active_reset+0x530/0xa20 net/ipv4/tcp_output.c:3828
 mptcp_do_fastclose+0x26f/0x3b0 net/mptcp/protocol.c:2792
 mptcp_disconnect+0x223/0x880 net/mptcp/protocol.c:3252
 mptcp_sendmsg_fastopen net/mptcp/protocol.c:1775 [inline]
 mptcp_sendmsg+0x157e/0x1ec0 net/mptcp/protocol.c:1854
 inet6_sendmsg+0x11c/0x140 net/ipv6/af_inet6.c:659
 sock_sendmsg_nosec net/socket.c:727 [inline]
 __sock_sendmsg net/socket.c:742 [inline]
 ____sys_sendmsg+0x705/0xc70 net/socket.c:2630
 ___sys_sendmsg+0x134/0x1d0 net/socket.c:2684
 __sys_sendmsg+0x16d/0x220 net/socket.c:2716
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f4e5498f749
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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f4e558f4038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f4e54be5fa0 RCX: 00007f4e5498f749
RDX: 0000000004040845 RSI: 0000200000000680 RDI: 0000000000000003
RBP: 00007f4e558f4090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007f4e54be6038 R14: 00007f4e54be5fa0 R15: 00007fff219d8fb8
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:__tcp_select_window+0x5a8/0x12e0 net/ipv4/tcp_output.c:3333
Code: 45 01 e7 44 89 ff e8 77 16 f0 f7 45 39 f7 0f 8d 11 ff ff ff e8 e9 1b f0 f7 45 89 f4 e9 04 ff ff ff e8 dc 1b f0 f7 44 89 f0 99 <f7> 7c 24 14 41 29 d6 45 89 f4 e9 ec fe ff ff e8 c4 1b f0 f7 48 89
RSP: 0018:ffffc90005e875a0 EFLAGS: 00010293
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff89cccb8d
RDX: 0000000000000000 RSI: ffffffff89cccbf4 RDI: 0000000000000004
RBP: 0000000000000000 R08: 0000000000000004 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000000
R13: ffff88802b876d40 R14: 0000000000000000 R15: 0000000000000000
FS:  00007f4e558f46c0(0000) GS:ffff888124a05000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000000180 CR3: 000000005218b000 CR4: 00000000003526f0
----------------
Code disassembly (best guess):
   0:	45 01 e7             	add    %r12d,%r15d
   3:	44 89 ff             	mov    %r15d,%edi
   6:	e8 77 16 f0 f7       	call   0xf7f01682
   b:	45 39 f7             	cmp    %r14d,%r15d
   e:	0f 8d 11 ff ff ff    	jge    0xffffff25
  14:	e8 e9 1b f0 f7       	call   0xf7f01c02
  19:	45 89 f4             	mov    %r14d,%r12d
  1c:	e9 04 ff ff ff       	jmp    0xffffff25
  21:	e8 dc 1b f0 f7       	call   0xf7f01c02
  26:	44 89 f0             	mov    %r14d,%eax
  29:	99                   	cltd
* 2a:	f7 7c 24 14          	idivl  0x14(%rsp) <-- trapping instruction
  2e:	41 29 d6             	sub    %edx,%r14d
  31:	45 89 f4             	mov    %r14d,%r12d
  34:	e9 ec fe ff ff       	jmp    0xffffff25
  39:	e8 c4 1b f0 f7       	call   0xf7f01c02
  3e:	48                   	rex.W
  3f:	89                   	.byte 0x89