mct_u232 ttyUSB0: Set MODEM CTRL 0xb failed (error = -71) mct_u232 ttyUSB0: Set LINE CTRL 0x3 failed (error = -71) mct_u232 ttyUSB0: Get MODEM STATus failed (error = -19) Oops: general protection fault, probably for non-canonical address 0xdffffc000000000a: 0000 [#1] SMP KASAN PTI KASAN: null-ptr-deref in range [0x0000000000000050-0x0000000000000057] CPU: 0 UID: 0 PID: 7953 Comm: syz.6.552 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/15/2026 RIP: 0010:mct_u232_open+0x39c/0x680 drivers/usb/serial/mct_u232.c:460 Code: 8d 9e 20 04 00 00 48 89 d8 48 c1 e8 03 42 80 3c 38 00 74 08 48 89 df e8 62 c3 6e fa 48 8b 1b 48 83 c3 50 48 89 d8 48 c1 e8 03 <42> 0f b6 04 38 84 c0 0f 85 a7 01 00 00 8b 13 49 81 c6 40 05 00 00 RSP: 0000:ffffc900039c7760 EFLAGS: 00010206 RAX: 000000000000000a RBX: 0000000000000050 RCX: 0000000000080000 RDX: ffffc900136d9000 RSI: 0000000000002883 RDI: 0000000000002884 RBP: 00000000ffffffed R08: ffffffff91e120bf R09: 1ffffffff23c2417 R10: dffffc0000000000 R11: fffffbfff23c2418 R12: 1ffff11006506e30 R13: dffffc0000000000 R14: ffff88802b2aa000 R15: dffffc0000000000 FS: 00007f9c5f8e66c0(0000) GS:ffff888123159000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000110c26aa5e CR3: 000000005c1c4000 CR4: 00000000003526f0 Call Trace: serial_port_activate+0x151/0x250 drivers/usb/serial/usb-serial.c:268 tty_port_open+0x1df/0x2d0 drivers/tty/tty_port.c:798 tty_open+0x48a/0xd80 drivers/tty/tty_io.c:2112 chrdev_open+0x4d9/0x600 fs/char_dev.c:413 do_dentry_open+0x80e/0x1360 fs/open.c:1000 vfs_open_consume+0x4a/0x350 fs/open.c:1131 do_open fs/namei.c:4851 [inline] path_openat+0x16fc/0x20f0 fs/namei.c:5016 do_file_open+0x23e/0x4a0 fs/namei.c:5045 do_sys_openat2+0x115/0x200 fs/open.c:1443 do_sys_open fs/open.c:1449 [inline] __do_sys_openat fs/open.c:1789 [inline] __se_sys_openat fs/open.c:1784 [inline] __x64_sys_openat+0x138/0x170 fs/open.c:1784 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x16a/0x530 arch/x86/entry/syscall_64.c:89 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x00007f9c5e99fb19 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f9c5f8e6028 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007f9c5ec25fa0 RCX: 00007f9c5e99fb19 RDX: 0000000000000000 RSI: 0000200000000200 RDI: ffffffffffffff9c RBP: 00007f9c5ea37b70 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f9c5ec26038 R14: 00007f9c5ec25fa0 R15: 00007ffcfa0775a8 Modules linked in: ---[ end trace 0000000000000000 ]--- RIP: 0010:mct_u232_open+0x39c/0x680 drivers/usb/serial/mct_u232.c:460 Code: 8d 9e 20 04 00 00 48 89 d8 48 c1 e8 03 42 80 3c 38 00 74 08 48 89 df e8 62 c3 6e fa 48 8b 1b 48 83 c3 50 48 89 d8 48 c1 e8 03 <42> 0f b6 04 38 84 c0 0f 85 a7 01 00 00 8b 13 49 81 c6 40 05 00 00 RSP: 0000:ffffc900039c7760 EFLAGS: 00010206 RAX: 000000000000000a RBX: 0000000000000050 RCX: 0000000000080000 RDX: ffffc900136d9000 RSI: 0000000000002883 RDI: 0000000000002884 RBP: 00000000ffffffed R08: ffffffff91e120bf R09: 1ffffffff23c2417 R10: dffffc0000000000 R11: fffffbfff23c2418 R12: 1ffff11006506e30 R13: dffffc0000000000 R14: ffff88802b2aa000 R15: dffffc0000000000 FS: 00007f9c5f8e66c0(0000) GS:ffff888123259000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f3f47088286 CR3: 000000005c1c4000 CR4: 00000000003526f0 ---------------- Code disassembly (best guess): 0: 8d 9e 20 04 00 00 lea 0x420(%rsi),%ebx 6: 48 89 d8 mov %rbx,%rax 9: 48 c1 e8 03 shr $0x3,%rax d: 42 80 3c 38 00 cmpb $0x0,(%rax,%r15,1) 12: 74 08 je 0x1c 14: 48 89 df mov %rbx,%rdi 17: e8 62 c3 6e fa call 0xfa6ec37e 1c: 48 8b 1b mov (%rbx),%rbx 1f: 48 83 c3 50 add $0x50,%rbx 23: 48 89 d8 mov %rbx,%rax 26: 48 c1 e8 03 shr $0x3,%rax * 2a: 42 0f b6 04 38 movzbl (%rax,%r15,1),%eax <-- trapping instruction 2f: 84 c0 test %al,%al 31: 0f 85 a7 01 00 00 jne 0x1de 37: 8b 13 mov (%rbx),%edx 39: 49 81 c6 40 05 00 00 add $0x540,%r14