entry_SYSCALL_64_after_hwframe+0x5c/0xc1 ---[ end trace 25474f664d9331fc ]--- 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 CPU: 0 PID: 30243 Comm: syz-executor.5 Tainted: G W 5.4.225-syzkaller-00029-g6a5ec6cea0cd #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/12/2023 RIP: 0010:strlen+0x2a/0x60 lib/string.c:552 Code: 41 57 41 56 41 54 53 49 89 fe 48 c7 c0 ff ff ff ff 49 bf 00 00 00 00 00 fc ff df 48 89 fb 66 90 49 89 c4 48 89 d8 48 c1 e8 03 <42> 0f b6 04 38 84 c0 75 12 48 ff c3 49 8d 44 24 01 43 80 7c 26 01 RSP: 0018:ffff8881e989f9b8 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000040000 RDX: ffffc90002556000 RSI: 000000000003ffff RDI: 0000000000000000 RBP: 0000000000000000 R08: ffffffff81b9e5d9 R09: ffffed103d313f3d R10: ffffed103d313f3d R11: 1ffff1103d313f3c R12: ffffffffffffffff R13: 0000000000000000 R14: 0000000000000000 R15: dffffc0000000000 FS: 00007f87bcb38700(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f000dd5e988 CR3: 00000001cf740000 CR4: 00000000003406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: kernfs_name_hash+0x1e/0x220 fs/kernfs/dir.c:310 kernfs_find_ns+0x6b/0x260 fs/kernfs/dir.c:855 kernfs_remove_by_name_ns+0x33/0x100 fs/kernfs/dir.c:1517 del_gendisk+0x98a/0xbf0 block/genhd.c:833 loop_remove+0x42/0xa0 drivers/block/loop.c:2194 loop_control_ioctl+0x67f/0x740 drivers/block/loop.c:2293 do_vfs_ioctl+0x744/0x1730 fs/ioctl.c:47 ksys_ioctl fs/ioctl.c:742 [inline] __do_sys_ioctl fs/ioctl.c:749 [inline] __se_sys_ioctl fs/ioctl.c:747 [inline] __x64_sys_ioctl+0xd4/0x110 fs/ioctl.c:747 do_syscall_64+0xcb/0x1c0 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x5c/0xc1 Modules linked in: ---[ end trace 25474f664d9331fd ]--- RIP: 0010:strlen+0x2a/0x60 lib/string.c:552 Code: 41 57 41 56 41 54 53 49 89 fe 48 c7 c0 ff ff ff ff 49 bf 00 00 00 00 00 fc ff df 48 89 fb 66 90 49 89 c4 48 89 d8 48 c1 e8 03 <42> 0f b6 04 38 84 c0 75 12 48 ff c3 49 8d 44 24 01 43 80 7c 26 01 RSP: 0018:ffff8881e989f9b8 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000040000 RDX: ffffc90002556000 RSI: 000000000003ffff RDI: 0000000000000000 RBP: 0000000000000000 R08: ffffffff81b9e5d9 R09: ffffed103d313f3d R10: ffffed103d313f3d R11: 1ffff1103d313f3c R12: ffffffffffffffff R13: 0000000000000000 R14: 0000000000000000 R15: dffffc0000000000 FS: 00007f87bcb38700(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f000dd5e988 CR3: 00000001cf740000 CR4: 00000000003406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 ---------------- Code disassembly (best guess): 0: 41 57 push %r15 2: 41 56 push %r14 4: 41 54 push %r12 6: 53 push %rbx 7: 49 89 fe mov %rdi,%r14 a: 48 c7 c0 ff ff ff ff mov $0xffffffffffffffff,%rax 11: 49 bf 00 00 00 00 00 movabs $0xdffffc0000000000,%r15 18: fc ff df 1b: 48 89 fb mov %rdi,%rbx 1e: 66 90 xchg %ax,%ax 20: 49 89 c4 mov %rax,%r12 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: 75 12 jne 0x45 33: 48 ff c3 inc %rbx 36: 49 8d 44 24 01 lea 0x1(%r12),%rax 3b: 43 rex.XB 3c: 80 .byte 0x80 3d: 7c 26 jl 0x65 3f: 01 .byte 0x1