kasan: CONFIG_KASAN_INLINE enabled kasan: GPF could be caused by NULL-ptr deref or user memory access general protection fault: 0000 [#1] PREEMPT SMP KASAN Modules linked in: CPU: 1 PID: 19900 Comm: syz-executor.5 Not tainted 4.14.289-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/29/2022 task: ffff88807c516480 task.stack: ffff88807c9b8000 RIP: 0010:cdev_del+0x22/0x90 fs/char_dev.c:602 RSP: 0018:ffff88807c9bfba0 EFLAGS: 00010207 RAX: dffffc0000000000 RBX: ffff8880b0bd1800 RCX: ffffc900069e9000 RDX: 000000000000000c RSI: ffffffff8187c22d RDI: 0000000000000064 RBP: 0000000000000000 R08: ffffffff8b9d7bf8 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffff8880b0bd1808 R13: ffff8880af067208 R14: ffff8880b4227f40 R15: ffff8880a147f2b0 FS: 00007fb92a768700(0000) GS:ffff8880ba500000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fd91003d088 CR3: 0000000099d3d000 CR4: 00000000003406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: tty_unregister_device drivers/tty/tty_io.c:3046 [inline] tty_unregister_device+0x101/0x1a0 drivers/tty/tty_io.c:3041 gsmld_detach_gsm drivers/tty/n_gsm.c:2309 [inline] gsmld_close+0xaa/0x1f0 drivers/tty/n_gsm.c:2378 tty_ldisc_close+0x8c/0xc0 drivers/tty/tty_ldisc.c:505 tty_set_ldisc+0x1b3/0x5d0 drivers/tty/tty_ldisc.c:600 tiocsetd drivers/tty/tty_io.c:2351 [inline] tty_ioctl+0xa2a/0x1430 drivers/tty/tty_io.c:2595 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:500 [inline] do_vfs_ioctl+0x75a/0xff0 fs/ioctl.c:684 SYSC_ioctl fs/ioctl.c:701 [inline] SyS_ioctl+0x7f/0xb0 fs/ioctl.c:692 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x7fb92bdf3209 RSP: 002b:00007fb92a768168 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007fb92bf05f60 RCX: 00007fb92bdf3209 RDX: 0000000020000040 RSI: 0000000000005423 RDI: 0000000000000003 RBP: 00007fb92be4d161 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffcfa3ab59f R14: 00007fb92a768300 R15: 0000000000022000 Code: 05 3e f7 ff eb d2 0f 1f 00 55 48 89 fd 48 83 ec 08 e8 f3 84 cd ff 48 8d 7d 64 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <0f> b6 14 02 48 89 f8 83 e0 07 83 c0 03 38 d0 7c 04 84 d2 75 4f RIP: cdev_del+0x22/0x90 fs/char_dev.c:602 RSP: ffff88807c9bfba0 ---[ end trace 79ef5b9c9324a1a8 ]--- ---------------- Code disassembly (best guess), 1 bytes skipped: 0: 3e f7 ff ds idiv %edi 3: eb d2 jmp 0xffffffd7 5: 0f 1f 00 nopl (%rax) 8: 55 push %rbp 9: 48 89 fd mov %rdi,%rbp c: 48 83 ec 08 sub $0x8,%rsp 10: e8 f3 84 cd ff callq 0xffcd8508 15: 48 8d 7d 64 lea 0x64(%rbp),%rdi 19: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax 20: fc ff df 23: 48 89 fa mov %rdi,%rdx 26: 48 c1 ea 03 shr $0x3,%rdx * 2a: 0f b6 14 02 movzbl (%rdx,%rax,1),%edx <-- trapping instruction 2e: 48 89 f8 mov %rdi,%rax 31: 83 e0 07 and $0x7,%eax 34: 83 c0 03 add $0x3,%eax 37: 38 d0 cmp %dl,%al 39: 7c 04 jl 0x3f 3b: 84 d2 test %dl,%dl 3d: 75 4f jne 0x8e