Oops: divide error: 0000 [#1] SMP KASAN PTI CPU: 1 UID: 0 PID: 26750 Comm: syz.4.6011 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+0x824/0x1320 net/ipv4/tcp_output.c:3336 Code: ff ff ff 44 89 f1 d3 e0 89 c1 f7 d1 41 01 cc 41 21 c4 e9 a9 00 00 00 e8 da 10 01 f8 e9 9c 00 00 00 e8 d0 10 01 f8 44 89 e0 99 7c 24 1c 41 29 d4 48 bb 00 00 00 00 00 fc ff df e9 80 00 00 00 RSP: 0018:ffffc9000f7f7aa0 EFLAGS: 00010283 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000080000 RDX: 0000000000000000 RSI: 00000000000000f7 RDI: 00000000000000f8 RBP: ffffc9000f7f7b90 R08: ffff888075c98dc3 R09: 1ffff1100eb931b8 R10: dffffc0000000000 R11: ffffed100eb931b9 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 FS: 00007fc7799d76c0(0000) GS:ffff888126235000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000110c348e19 CR3: 000000008db5c000 CR4: 00000000003526f0 Call Trace: tcp_select_window net/ipv4/tcp_output.c:281 [inline] __tcp_transmit_skb+0xbc7/0x3aa0 net/ipv4/tcp_output.c:1568 tcp_transmit_skb net/ipv4/tcp_output.c:1649 [inline] tcp_send_active_reset+0x2d1/0x5b0 net/ipv4/tcp_output.c:3836 mptcp_do_fastclose+0x286/0x390 net/mptcp/protocol.c:2887 mptcp_disconnect+0x238/0x730 net/mptcp/protocol.c:3371 inet_shutdown+0x1c4/0x390 net/ipv4/af_inet.c:943 __sys_shutdown_sock net/socket.c:2470 [inline] __sys_shutdown net/socket.c:2486 [inline] __do_sys_shutdown net/socket.c:2491 [inline] __se_sys_shutdown net/socket.c:2489 [inline] __x64_sys_shutdown+0x13f/0x1a0 net/socket.c:2489 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fc778b8f749 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:00007fc7799d7038 EFLAGS: 00000246 ORIG_RAX: 0000000000000030 RAX: ffffffffffffffda RBX: 00007fc778de5fa0 RCX: 00007fc778b8f749 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003 RBP: 00007fc778c13f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fc778de6038 R14: 00007fc778de5fa0 R15: 00007ffdda29c4b8 Modules linked in: ---[ end trace 0000000000000000 ]--- RIP: 0010:__tcp_select_window+0x824/0x1320 net/ipv4/tcp_output.c:3336 Code: ff ff ff 44 89 f1 d3 e0 89 c1 f7 d1 41 01 cc 41 21 c4 e9 a9 00 00 00 e8 da 10 01 f8 e9 9c 00 00 00 e8 d0 10 01 f8 44 89 e0 99 7c 24 1c 41 29 d4 48 bb 00 00 00 00 00 fc ff df e9 80 00 00 00 RSP: 0018:ffffc9000f7f7aa0 EFLAGS: 00010283 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000080000 RDX: 0000000000000000 RSI: 00000000000000f7 RDI: 00000000000000f8 RBP: ffffc9000f7f7b90 R08: ffff888075c98dc3 R09: 1ffff1100eb931b8 R10: dffffc0000000000 R11: ffffed100eb931b9 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 FS: 00007fc7799d76c0(0000) GS:ffff888126135000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fc7799b5f98 CR3: 000000008db5c000 CR4: 00000000003526f0 ---------------- Code disassembly (best guess), 2 bytes skipped: 0: ff 44 89 f1 incl -0xf(%rcx,%rcx,4) 4: d3 e0 shl %cl,%eax 6: 89 c1 mov %eax,%ecx 8: f7 d1 not %ecx a: 41 01 cc add %ecx,%r12d d: 41 21 c4 and %eax,%r12d 10: e9 a9 00 00 00 jmp 0xbe 15: e8 da 10 01 f8 call 0xf80110f4 1a: e9 9c 00 00 00 jmp 0xbb 1f: e8 d0 10 01 f8 call 0xf80110f4 24: 44 89 e0 mov %r12d,%eax 27: 99 cltd * 28: f7 7c 24 1c idivl 0x1c(%rsp) <-- trapping instruction 2c: 41 29 d4 sub %edx,%r12d 2f: 48 bb 00 00 00 00 00 movabs $0xdffffc0000000000,%rbx 36: fc ff df 39: e9 80 00 00 00 jmp 0xbe