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: 27013 Comm: syz-executor.2 Not tainted 4.14.274-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 task: ffff8880a2392500 task.stack: ffff88809f030000 RIP: 0010:cdev_del+0x22/0x90 fs/char_dev.c:602 RSP: 0018:ffff88809f037ca0 EFLAGS: 00010207 RAX: dffffc0000000000 RBX: ffff8882384e8000 RCX: 0000000000000000 RDX: 000000000000000c RSI: ffff8880a2392db0 RDI: 0000000000000064 RBP: 0000000000000000 R08: ffffffff8b9cdce0 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffff8882384e8008 R13: ffff888238541348 R14: ffff8880a9daae80 R15: ffff8880a9a3e198 FS: 000055555638c400(0000) GS:ffff8880ba500000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffd25857fa8 CR3: 000000009856e000 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:2305 [inline] gsmld_close+0xaa/0x1f0 drivers/tty/n_gsm.c:2374 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: 0033:0x7f4e377a2c8b RSP: 002b:00007ffe257a94c0 EFLAGS: 00000293 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 0000000000000005 RCX: 00007f4e377a2c8b RDX: 0000000000000000 RSI: 0000001b2d021530 RDI: 0000000000000004 RBP: 00007f4e37904960 R08: 0000000000000000 R09: 0000000064a32d66 R10: 0000000000000000 R11: 0000000000000293 R12: 00000000002d2837 R13: 00007ffe257a95c0 R14: 00007ffe257a95e0 R15: 0000000000000032 Code: e5 44 f7 ff eb d2 0f 1f 00 55 48 89 fd 48 83 ec 08 e8 e3 93 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: ffff88809f037ca0 ---[ end trace 647df888233e97aa ]--- ---------------- Code disassembly (best guess): 0: e5 44 in $0x44,%eax 2: f7 ff idiv %edi 4: eb d2 jmp 0xffffffd8 6: 0f 1f 00 nopl (%rax) 9: 55 push %rbp a: 48 89 fd mov %rdi,%rbp d: 48 83 ec 08 sub $0x8,%rsp 11: e8 e3 93 cd ff callq 0xffcd93f9 16: 48 8d 7d 64 lea 0x64(%rbp),%rdi 1a: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax 21: fc ff df 24: 48 89 fa mov %rdi,%rdx 27: 48 c1 ea 03 shr $0x3,%rdx * 2b: 0f b6 14 02 movzbl (%rdx,%rax,1),%edx <-- trapping instruction 2f: 48 89 f8 mov %rdi,%rax 32: 83 e0 07 and $0x7,%eax 35: 83 c0 03 add $0x3,%eax 38: 38 d0 cmp %dl,%al 3a: 7c 04 jl 0x40 3c: 84 d2 test %dl,%dl 3e: 75 4f jne 0x8f