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+0xca/0x1c0 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x5c/0xc1 ---[ end trace 1f712247c93ec33a ]--- 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: 1 PID: 419 Comm: syz-executor.0 Tainted: G W 5.4.233-syzkaller-00003-gf423d52eea72 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/28/2023 RIP: 0010:kill_device drivers/base/core.c:3022 [inline] RIP: 0010:device_del+0xe7/0xfa0 drivers/base/core.c:3049 Code: df e8 7d 30 ff fe 4c 89 7c 24 18 41 bf c8 00 00 00 48 89 5c 24 08 4c 03 3b 4d 89 fc 49 c1 ec 03 48 b8 00 00 00 00 00 fc ff df <41> 0f b6 04 04 84 c0 0f 85 31 0e 00 00 41 0f b6 1f 89 de 83 e6 01 RSP: 0018:ffff8881ee3af9c0 EFLAGS: 00010202 RAX: dffffc0000000000 RBX: ffff8881f053c0d8 RCX: 1ffff1103e0a781b RDX: 0000000000000001 RSI: 0000000000000008 RDI: ffff8881ee3af940 RBP: ffff8881ee3afa90 R08: dffffc0000000000 R09: ffffed103dc75f29 R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000000019 R13: ffff8881f053c070 R14: ffff8881f053c110 R15: 00000000000000c8 FS: 00007f3d3dca0700(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fff128c5d18 CR3: 00000001db0b0000 CR4: 00000000003406a0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: del_gendisk+0x9d9/0xc30 block/genhd.c:835 loop_remove+0x42/0xa0 drivers/block/loop.c:2194 loop_control_ioctl+0x564/0x620 drivers/block/loop.c:2293 do_vfs_ioctl+0x742/0x1720 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+0xca/0x1c0 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x5c/0xc1 Modules linked in: ---[ end trace 1f712247c93ec33b ]--- RIP: 0010:kill_device drivers/base/core.c:3022 [inline] RIP: 0010:device_del+0xe7/0xfa0 drivers/base/core.c:3049 Code: df e8 7d 30 ff fe 4c 89 7c 24 18 41 bf c8 00 00 00 48 89 5c 24 08 4c 03 3b 4d 89 fc 49 c1 ec 03 48 b8 00 00 00 00 00 fc ff df <41> 0f b6 04 04 84 c0 0f 85 31 0e 00 00 41 0f b6 1f 89 de 83 e6 01 RSP: 0018:ffff8881ee3af9c0 EFLAGS: 00010202 RAX: dffffc0000000000 RBX: ffff8881f053c0d8 RCX: 1ffff1103e0a781b RDX: 0000000000000001 RSI: 0000000000000008 RDI: ffff8881ee3af940 RBP: ffff8881ee3afa90 R08: dffffc0000000000 R09: ffffed103dc75f29 R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000000019 R13: ffff8881f053c070 R14: ffff8881f053c110 R15: 00000000000000c8 FS: 00007f3d3dca0700(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fff128c5d18 CR3: 00000001db0b0000 CR4: 00000000003406a0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 ---------------- Code disassembly (best guess), 1 bytes skipped: 0: e8 7d 30 ff fe callq 0xfeff3082 5: 4c 89 7c 24 18 mov %r15,0x18(%rsp) a: 41 bf c8 00 00 00 mov $0xc8,%r15d 10: 48 89 5c 24 08 mov %rbx,0x8(%rsp) 15: 4c 03 3b add (%rbx),%r15 18: 4d 89 fc mov %r15,%r12 1b: 49 c1 ec 03 shr $0x3,%r12 1f: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax 26: fc ff df * 29: 41 0f b6 04 04 movzbl (%r12,%rax,1),%eax <-- trapping instruction 2e: 84 c0 test %al,%al 30: 0f 85 31 0e 00 00 jne 0xe67 36: 41 0f b6 1f movzbl (%r15),%ebx 3a: 89 de mov %ebx,%esi 3c: 83 e6 01 and $0x1,%esi