Oops: general protection fault, probably for non-canonical address 0xdffffc0000000007: 0000 [#1] SMP KASAN NOPTI
KASAN: null-ptr-deref in range [0x0000000000000038-0x000000000000003f]
CPU: 3 UID: 0 PID: 13289 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
RIP: 0010:rb_first include/linux/rbtree.h:54 [inline]
RIP: 0010:simple_xattrs_free+0x60/0x1e0 fs/xattr.c:1564
Code: ea 03 80 3c 02 00 0f 85 8b 01 00 00 49 c7 45 00 00 00 00 00 e8 21 9c 75 ff 4c 89 fa 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 <80> 3c 02 00 0f 85 56 01 00 00 48 bd 00 00 00 00 00 fc ff df 49 8b
RSP: 0018:ffffc90004b3fae0 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: ffff88802d02c1e0 RCX: ffffffff826a4375
RDX: 0000000000000007 RSI: ffffffff82494a4f RDI: 0000000000000038
RBP: ffff88802d02c278 R08: 0000000000000005 R09: 0000000000000000
R10: 00000000ffffffea R11: ffff8880560e8b30 R12: 1ffff92000967f6b
R13: 0000000000000000 R14: ffff8880548c7320 R15: 0000000000000038
FS:  0000555559bea500(0000) GS:ffff8880d6bf5000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f8445665e00 CR3: 000000002789e000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 __kernfs_new_node+0x7b4/0x990 fs/kernfs/dir.c:684
 kernfs_new_node+0x13c/0x1e0 fs/kernfs/dir.c:716
 kernfs_create_dir_ns+0x4c/0x1a0 fs/kernfs/dir.c:1086
 cgroup_create kernel/cgroup/cgroup.c:5859 [inline]
 cgroup_mkdir+0x40f/0x12e0 kernel/cgroup/cgroup.c:6007
 kernfs_iop_mkdir+0x111/0x190 fs/kernfs/dir.c:1271
 vfs_mkdir+0x731/0xb60 fs/namei.c:5130
 do_mkdirat+0x442/0x5e0 fs/namei.c:5164
 __do_sys_mkdirat fs/namei.c:5186 [inline]
 __se_sys_mkdirat fs/namei.c:5184 [inline]
 __x64_sys_mkdirat+0x83/0xb0 fs/namei.c:5184
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f844578df17
Code: 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 02 01 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffca53d9268 EFLAGS: 00000202 ORIG_RAX: 0000000000000102
RAX: ffffffffffffffda RBX: 00007ffca53d92c0 RCX: 00007f844578df17
RDX: 00000000000001ff RSI: 00007ffca53d92c0 RDI: 00000000ffffff9c
RBP: 0000000000000001 R08: 0000000000000017 R09: 00007ffca53d8fb7
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000008
R13: 0000000000000003 R14: 00007ffca53d9738 R15: 0000000000000000
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:rb_first include/linux/rbtree.h:54 [inline]
RIP: 0010:simple_xattrs_free+0x60/0x1e0 fs/xattr.c:1564
Code: ea 03 80 3c 02 00 0f 85 8b 01 00 00 49 c7 45 00 00 00 00 00 e8 21 9c 75 ff 4c 89 fa 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 <80> 3c 02 00 0f 85 56 01 00 00 48 bd 00 00 00 00 00 fc ff df 49 8b
RSP: 0018:ffffc90004b3fae0 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: ffff88802d02c1e0 RCX: ffffffff826a4375
RDX: 0000000000000007 RSI: ffffffff82494a4f RDI: 0000000000000038
RBP: ffff88802d02c278 R08: 0000000000000005 R09: 0000000000000000
R10: 00000000ffffffea R11: ffff8880560e8b30 R12: 1ffff92000967f6b
R13: 0000000000000000 R14: ffff8880548c7320 R15: 0000000000000038
FS:  0000555559bea500(0000) GS:ffff8880d6bf5000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f8445665e00 CR3: 000000002789e000 CR4: 0000000000352ef0
----------------
Code disassembly (best guess), 1 bytes skipped:
   0:	03 80 3c 02 00 0f    	add    0xf00023c(%rax),%eax
   6:	85 8b 01 00 00 49    	test   %ecx,0x49000001(%rbx)
   c:	c7 45 00 00 00 00 00 	movl   $0x0,0x0(%rbp)
  13:	e8 21 9c 75 ff       	call   0xff759c39
  18:	4c 89 fa             	mov    %r15,%rdx
  1b:	48 b8 00 00 00 00 00 	movabs $0xdffffc0000000000,%rax
  22:	fc ff df
  25:	48 c1 ea 03          	shr    $0x3,%rdx
* 29:	80 3c 02 00          	cmpb   $0x0,(%rdx,%rax,1) <-- trapping instruction
  2d:	0f 85 56 01 00 00    	jne    0x189
  33:	48 bd 00 00 00 00 00 	movabs $0xdffffc0000000000,%rbp
  3a:	fc ff df
  3d:	49                   	rex.WB
  3e:	8b                   	.byte 0x8b