Oops: general protection fault, probably for non-canonical address 0xdffffc0000000007: 0000 [#1] SMP KASAN NOPTI
KASAN: null-ptr-deref in range [0x0000000000000038-0x000000000000003f]
CPU: 0 UID: 0 PID: 28259 Comm: syz.1.6791 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
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:ffffc9000d667680 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: ffff88802a417f00 RCX: ffffc9002b002000
RDX: 0000000000000007 RSI: ffffffff82494a4f RDI: 0000000000000038
RBP: ffff88802a417f98 R08: 0000000000000005 R09: 0000000000000000
R10: 00000000ffffffea R11: ffff888029678b30 R12: 1ffff92001accedf
R13: 0000000000000000 R14: ffff8881055ffd40 R15: 0000000000000038
FS:  00007fb96657b6c0(0000) GS:ffff8880d68f5000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c2c3e14 CR3: 0000000037fc0000 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_file+0x53/0x350 fs/kernfs/file.c:1057
 cgroup_add_file kernel/cgroup/cgroup.c:4421 [inline]
 cgroup_addrm_files+0x546/0xc20 kernel/cgroup/cgroup.c:4475
 css_populate_dir+0x169/0x570 kernel/cgroup/cgroup.c:1834
 cgroup_apply_control_enable+0x3f3/0xbb0 kernel/cgroup/cgroup.c:3399
 cgroup_apply_control kernel/cgroup/cgroup.c:3473 [inline]
 cgroup_subtree_control_write+0xb47/0xef0 kernel/cgroup/cgroup.c:3627
 cgroup_file_write+0x1ef/0x7a0 kernel/cgroup/cgroup.c:4312
 kernfs_fop_write_iter+0x3af/0x570 fs/kernfs/file.c:352
 new_sync_write fs/read_write.c:593 [inline]
 vfs_write+0x7d3/0x11d0 fs/read_write.c:686
 ksys_write+0x12a/0x250 fs/read_write.c:738
 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: 0033:0x7fb96578f7c9
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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fb96657b038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fb9659e6180 RCX: 00007fb96578f7c9
RDX: 000000000000000e RSI: 0000200000000040 RDI: 000000000000000c
RBP: 00007fb965813f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fb9659e6218 R14: 00007fb9659e6180 R15: 00007ffc73067ef8
 </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:ffffc9000d667680 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: ffff88802a417f00 RCX: ffffc9002b002000
RDX: 0000000000000007 RSI: ffffffff82494a4f RDI: 0000000000000038
RBP: ffff88802a417f98 R08: 0000000000000005 R09: 0000000000000000
R10: 00000000ffffffea R11: ffff888029678b30 R12: 1ffff92001accedf
R13: 0000000000000000 R14: ffff8881055ffd40 R15: 0000000000000038
FS:  00007fb96657b6c0(0000) GS:ffff8880d68f5000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c2c3e14 CR3: 0000000037fc0000 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