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: 18431 Comm: syz-executor.5 Not tainted 4.14.290-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/22/2022 task: ffff888098d30640 task.stack: ffff888055d38000 RIP: 0010:cdev_del+0x22/0x90 fs/char_dev.c:602 RSP: 0018:ffff888055d3fca0 EFLAGS: 00010207 RAX: dffffc0000000000 RBX: ffff888238893a00 RCX: 0000000000000000 RDX: 000000000000000c RSI: ffff888098d30ef0 RDI: 0000000000000064 RBP: 0000000000000000 R08: ffffffff8b9d78d8 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffff888238893a08 R13: ffff8880af7709c8 R14: ffff8880af5c2440 R15: ffff888056f540e8 FS: 0000555555c55400(0000) GS:ffff8880ba500000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f299af09d38 CR3: 00000000a8c75000 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_ldisc_kill drivers/tty/tty_ldisc.c:651 [inline] tty_ldisc_release+0xe8/0x400 drivers/tty/tty_ldisc.c:818 tty_release_struct+0x20/0xe0 drivers/tty/tty_io.c:1603 tty_release+0xb3f/0x10d0 drivers/tty/tty_io.c:1776 __fput+0x25f/0x7a0 fs/file_table.c:210 task_work_run+0x11f/0x190 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:191 [inline] exit_to_usermode_loop+0x1ad/0x200 arch/x86/entry/common.c:164 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline] syscall_return_slowpath arch/x86/entry/common.c:270 [inline] do_syscall_64+0x4a3/0x640 arch/x86/entry/common.c:297 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x7f1de01d9ebb RSP: 002b:00007ffca57ac340 EFLAGS: 00000293 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 0000000000000004 RCX: 00007f1de01d9ebb RDX: 0000000000000000 RSI: 0000001b2de21458 RDI: 0000000000000003 RBP: 00007f1de033b980 R08: 0000000000000000 R09: 0000000004c6a598 R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000034972 R13: 00007ffca57ac440 R14: 00007ffca57ac460 R15: 0000000000000032 Code: 05 3e f7 ff eb d2 0f 1f 00 55 48 89 fd 48 83 ec 08 e8 e3 87 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: ffff888055d3fca0 ---[ end trace a256bd65d72f7a46 ]--- ---------------- 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 e3 87 cd ff callq 0xffcd87f8 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