Oops: divide error: 0000 [#1] SMP KASAN NOPTI CPU: 0 UID: 0 PID: 7280 Comm: syz.2.325 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 f7 13 f0 f7 45 39 f7 0f 8d 11 ff ff ff e8 69 19 f0 f7 45 89 f4 e9 04 ff ff ff e8 5c 19 f0 f7 44 89 f0 99 7c 24 14 41 29 d6 45 89 f4 e9 ec fe ff ff e8 44 19 f0 f7 48 89 RSP: 0018:ffffc90003447ad0 EFLAGS: 00010287 RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffc9000ca29000 RDX: 0000000000000000 RSI: ffffffff89ccce74 RDI: 0000000000000004 RBP: 0000000000000000 R08: 0000000000000004 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000000 R13: ffff88807c97d240 R14: 0000000000000000 R15: 0000000000000000 FS: 00007f801a79c6c0(0000) GS:ffff888124a05000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000110c39e018 CR3: 00000000a6f24000 CR4: 00000000003526f0 Call Trace: 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 inet_shutdown+0x26f/0x440 net/ipv4/af_inet.c:937 __sys_shutdown_sock net/socket.c:2470 [inline] __sys_shutdown_sock net/socket.c:2464 [inline] __sys_shutdown+0x116/0x1b0 net/socket.c:2486 __do_sys_shutdown net/socket.c:2491 [inline] __se_sys_shutdown net/socket.c:2489 [inline] __x64_sys_shutdown+0x53/0x80 net/socket.c:2489 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: 0033:0x7f801998f749 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:00007f801a79c038 EFLAGS: 00000246 ORIG_RAX: 0000000000000030 RAX: ffffffffffffffda RBX: 00007f8019be5fa0 RCX: 00007f801998f749 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003 RBP: 00007f8019a13f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f8019be6038 R14: 00007f8019be5fa0 R15: 00007ffe130f0a88 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 f7 13 f0 f7 45 39 f7 0f 8d 11 ff ff ff e8 69 19 f0 f7 45 89 f4 e9 04 ff ff ff e8 5c 19 f0 f7 44 89 f0 99 7c 24 14 41 29 d6 45 89 f4 e9 ec fe ff ff e8 44 19 f0 f7 48 89 RSP: 0018:ffffc90003447ad0 EFLAGS: 00010287 RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffc9000ca29000 RDX: 0000000000000000 RSI: ffffffff89ccce74 RDI: 0000000000000004 RBP: 0000000000000000 R08: 0000000000000004 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000000 R13: ffff88807c97d240 R14: 0000000000000000 R15: 0000000000000000 FS: 00007f801a79c6c0(0000) GS:ffff888124b05000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000110c33e6d7 CR3: 00000000a6f24000 CR4: 00000000003526f0 ---------------- Code disassembly (best guess): 0: 45 01 e7 add %r12d,%r15d 3: 44 89 ff mov %r15d,%edi 6: e8 f7 13 f0 f7 call 0xf7f01402 b: 45 39 f7 cmp %r14d,%r15d e: 0f 8d 11 ff ff ff jge 0xffffff25 14: e8 69 19 f0 f7 call 0xf7f01982 19: 45 89 f4 mov %r14d,%r12d 1c: e9 04 ff ff ff jmp 0xffffff25 21: e8 5c 19 f0 f7 call 0xf7f01982 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 44 19 f0 f7 call 0xf7f01982 3e: 48 rex.W 3f: 89 .byte 0x89