RBP: 00007f948c00c08d R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fff870ca2cf R14: 00007f948b128300 R15: 0000000000022000 ---[ end trace e58ba63927ee04ed ]--- general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] CPU: 0 PID: 21720 Comm: syz-executor.4 Tainted: G W 5.10.109-syzkaller-00693-g414e6c8e941c #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:strlen+0x3a/0x80 lib/string.c:568 Code: c0 ff ff ff ff 49 bf 00 00 00 00 00 fc ff df 48 89 fb 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 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:ffffc90009a8fb68 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000040000 RDX: ffffc90002113000 RSI: 000000000003ffff RDI: 0000000000000000 RBP: ffffc90009a8fb88 R08: ffffffff81d12c3c R09: fffff52001351f75 R10: fffff52001351f75 R11: 1ffff92001351f74 R12: ffffffffffffffff R13: 0000000000000000 R14: 0000000000000000 R15: dffffc0000000000 FS: 00007f948b128700(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b33321000 CR3: 000000010b93b000 CR4: 00000000003506b0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: kernfs_name_hash+0x21/0x240 fs/kernfs/dir.c:302 kernfs_find_ns+0x72/0x280 fs/kernfs/dir.c:841 kernfs_remove_by_name_ns+0x36/0x90 fs/kernfs/dir.c:1514 kernfs_remove_by_name include/linux/kernfs.h:608 [inline] sysfs_remove_link+0x50/0x60 fs/sysfs/symlink.c:152 del_gendisk+0xbe0/0xe20 block/genhd.c:951 loop_remove+0x46/0xb0 drivers/block/loop.c:2185 loop_control_ioctl+0x67f/0x740 drivers/block/loop.c:2284 vfs_ioctl fs/ioctl.c:48 [inline] __do_sys_ioctl fs/ioctl.c:753 [inline] __se_sys_ioctl+0x115/0x190 fs/ioctl.c:739 __x64_sys_ioctl+0x7b/0x90 fs/ioctl.c:739 do_syscall_64+0x34/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7f948bfb20e9 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f948b128168 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f948c0c4f60 RCX: 00007f948bfb20e9 RDX: 0000000000000000 RSI: 0000000000004c81 RDI: 0000000000000005 RBP: 00007f948c00c08d R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fff870ca2cf R14: 00007f948b128300 R15: 0000000000022000 Modules linked in: ---[ end trace e58ba63927ee04ee ]--- RIP: 0010:strlen+0x3a/0x80 lib/string.c:568 Code: c0 ff ff ff ff 49 bf 00 00 00 00 00 fc ff df 48 89 fb 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 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:ffffc90009a8fb68 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000040000 RDX: ffffc90002113000 RSI: 000000000003ffff RDI: 0000000000000000 RBP: ffffc90009a8fb88 R08: ffffffff81d12c3c R09: fffff52001351f75 R10: fffff52001351f75 R11: 1ffff92001351f74 R12: ffffffffffffffff R13: 0000000000000000 R14: 0000000000000000 R15: dffffc0000000000 FS: 00007f948b128700(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b33321000 CR3: 000000010b93b000 CR4: 00000000003506b0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 ---------------- Code disassembly (best guess), 5 bytes skipped: 0: 49 bf 00 00 00 00 00 movabs $0xdffffc0000000000,%r15 7: fc ff df a: 48 89 fb mov %rdi,%rbx d: 66 66 2e 0f 1f 84 00 data16 nopw %cs:0x0(%rax,%rax,1) 14: 00 00 00 00 18: 0f 1f 00 nopl (%rax) 1b: 49 89 c4 mov %rax,%r12 1e: 48 89 d8 mov %rbx,%rax 21: 48 c1 e8 03 shr $0x3,%rax * 25: 42 0f b6 04 38 movzbl (%rax,%r15,1),%eax <-- trapping instruction 2a: 84 c0 test %al,%al 2c: 75 12 jne 0x40 2e: 48 ff c3 inc %rbx 31: 49 8d 44 24 01 lea 0x1(%r12),%rax 36: 43 rex.XB 37: 80 .byte 0x80 38: 7c 26 jl 0x60 3a: 01 .byte 0x1