------------[ cut here ]------------
kernfs_put: syz4/pids.events: released with incorrect active_ref 0
WARNING: CPU: 0 PID: 83 at fs/kernfs/dir.c:531 kernfs_put.part.0+0x433/0x540
Modules linked in:
CPU: 0 PID: 83 Comm: kworker/0:2 Not tainted 5.19.0-rc4-next-20220701 #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014
Workqueue: events kernfs_notify_workfn
------------[ cut here ]------------
WARNING: CPU: 0 PID: 83 at fs/kernfs/dir.c:504 kernfs_get.part.0+0x69/0x80
Modules linked in:
CPU: 0 PID: 83 Comm: kworker/0:2 Not tainted 5.19.0-rc4-next-20220701 #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014
Workqueue: events kernfs_notify_workfn
RIP: 0010:kernfs_get.part.0+0x69/0x80
Code: 31 ff 89 ee e8 a8 43 a7 ff 85 ed 74 18 e8 cf 46 a7 ff be 04 00 00 00 48 89 df e8 52 be d9 ff f0 ff 03 5b 5d c3 e8 b7 46 a7 ff <0f> 0b eb df 48 89 df e8 fb ba d9 ff eb c6 66 0f 1f 84 00 00 00 00
RSP: 0018:ffff88806ce09c80 EFLAGS: 00010046
RAX: 0000000000000000 RBX: ffff88803725fcb0 RCX: 0000000000000100
RDX: ffff88800fb05040 RSI: ffffffff819d2579 RDI: 0000000000000005
RBP: 0000000000000000 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000001
R13: 1ffffffff0a01e40 R14: ffff88803725fcb0 R15: ffff8880386bfd30
FS:  0000000000000000(0000) GS:ffff88806ce00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f5382b758e0 CR3: 000000003a686000 CR4: 0000000000350ef0
Call Trace:
 <IRQ>
 kernfs_get+0x1b/0x30
 kernfs_notify+0x180/0x350
 cgroup_file_notify+0xf5/0x1a0
 call_timer_fn+0x17d/0x5f0
 __run_timers.part.0+0x65e/0xa50
 run_timer_softirq+0xae/0x1a0
 __do_softirq+0x1c8/0x8cc
 __irq_exit_rcu+0x113/0x170
 irq_exit_rcu+0x5/0x20
 sysvec_apic_timer_interrupt+0x8e/0xc0
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1b/0x20
RIP: 0010:console_emit_next_record.constprop.0+0x4c8/0x800
Code: 83 e2 07 38 d0 7f 08 84 c0 0f 85 d5 02 00 00 88 5d 00 e8 db 3e 00 00 31 ff 4c 89 f6 e8 91 3f 19 00 4d 85 f6 0f 85 76 01 00 00 <e8> 93 42 19 00 48 b8 00 00 00 00 00 fc ff df 48 03 04 24 48 c7 00
RSP: 0018:ffff88800fb0f578 EFLAGS: 00000202
RAX: 00000000003001d3 RBX: 0000000000000000 RCX: ffffffff8128663f
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffff88800fb0f720 R08: 0000000000000001 R09: ffffffff86a5c7c7
R10: fffffbfff0d4b8f8 R11: 0000000000000001 R12: 0000000000000001
R13: ffffffff86da8ba0 R14: 0000000000000200 R15: ffffffff855febd8
 console_unlock+0x36c/0x590
 vprintk_emit+0x1b9/0x550
 vprintk+0x80/0x90
 _printk+0xba/0xed
 print_worker_info.cold+0x59/0x5e
 dump_stack_print_info+0xf7/0x120
 show_regs+0x10/0x40
 __warn+0xe2/0x190
 report_bug+0x1bc/0x210
 handle_bug+0x3c/0x60
 exc_invalid_op+0x14/0x40
 asm_exc_invalid_op+0x1b/0x20
RIP: 0010:kernfs_put.part.0+0x433/0x540
Code: 03 80 3c 18 00 0f 85 ea 00 00 00 4d 8b 7d 38 e8 53 42 a7 ff 48 8b 14 24 44 89 f1 4c 89 fe 48 c7 c7 a0 58 72 84 e8 97 1c 6c 02 <0f> 0b e9 b9 fc ff ff 48 89 ef e8 8e b6 d9 ff e9 c1 fd ff ff e8 84
RSP: 0018:ffff88800fb0fbd8 EFLAGS: 00010286
RAX: 0000000000000000 RBX: dffffc0000000000 RCX: 0000000000000000
RDX: ffff88800fb05040 RSI: ffffffff812b6848 RDI: ffffed1001f61f6d
RBP: ffff88803725fce8 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000001 R12: ffff88803725fcb0
R13: ffff888037e0f910 R14: 0000000000000000 R15: ffff888019e63050
 kernfs_put+0x42/0x50
 kernfs_notify_workfn+0x417/0x560
 process_one_work+0xa0f/0x1690
 worker_thread+0x637/0x1250
 kthread+0x2ed/0x3a0
 ret_from_fork+0x22/0x30
 </TASK>
irq event stamp: 3146201
hardirqs last  enabled at (3146200): [<ffffffff841aba4f>] _raw_spin_unlock_irq+0x1f/0x40
hardirqs last disabled at (3146201): [<ffffffff841ab87e>] _raw_spin_lock_irqsave+0x4e/0x50
softirqs last  enabled at (3146136): [<ffffffff811662a3>] __irq_exit_rcu+0x113/0x170
softirqs last disabled at (3146197): [<ffffffff811662a3>] __irq_exit_rcu+0x113/0x170
---[ end trace 0000000000000000 ]---
RIP: 0010:kernfs_put.part.0+0x433/0x540
Code: 03 80 3c 18 00 0f 85 ea 00 00 00 4d 8b 7d 38 e8 53 42 a7 ff 48 8b 14 24 44 89 f1 4c 89 fe 48 c7 c7 a0 58 72 84 e8 97 1c 6c 02 <0f> 0b e9 b9 fc ff ff 48 89 ef e8 8e b6 d9 ff e9 c1 fd ff ff e8 84
RSP: 0018:ffff88800fb0fbd8 EFLAGS: 00010286
RAX: 0000000000000000 RBX: dffffc0000000000 RCX: 0000000000000000
RDX: ffff88800fb05040 RSI: ffffffff812b6848 RDI: ffffed1001f61f6d
RBP: ffff88803725fce8 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000001 R12: ffff88803725fcb0
R13: ffff888037e0f910 R14: 0000000000000000 R15: ffff888019e63050
FS:  0000000000000000(0000) GS:ffff88806ce00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f5382b758e0 CR3: 000000003a686000 CR4: 0000000000350ef0
Call Trace:
 <TASK>
 kernfs_put+0x42/0x50
 kernfs_notify_workfn+0x417/0x560
 process_one_work+0xa0f/0x1690
 worker_thread+0x637/0x1250
 kthread+0x2ed/0x3a0
 ret_from_fork+0x22/0x30
 </TASK>
irq event stamp: 3147907
hardirqs last  enabled at (3147917): [<ffffffff812af7a8>] __up_console_sem+0x78/0x80
hardirqs last disabled at (3147930): [<ffffffff812af78d>] __up_console_sem+0x5d/0x80
softirqs last  enabled at (3147414): [<ffffffff811662a3>] __irq_exit_rcu+0x113/0x170
softirqs last disabled at (3147247): [<ffffffff811662a3>] __irq_exit_rcu+0x113/0x170
---[ end trace 0000000000000000 ]---
==================================================================
BUG: KASAN: use-after-free in llist_del_first+0x89/0xa0
Read of size 8 at addr ffff88803725fd30 by task kworker/0:2/83

CPU: 0 PID: 83 Comm: kworker/0:2 Tainted: G        W         5.19.0-rc4-next-20220701 #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014
Workqueue: events kernfs_notify_workfn
Call Trace:
 <TASK>
 dump_stack_lvl+0x8b/0xb3
 print_report.cold+0x5e/0x5e1
 kasan_report+0xb1/0x1b0
 llist_del_first+0x89/0xa0
 kernfs_notify_workfn+0x78/0x560
 process_one_work+0xa0f/0x1690
 worker_thread+0x637/0x1250
 kthread+0x2ed/0x3a0
 ret_from_fork+0x22/0x30
 </TASK>

Allocated by task 530:
 kasan_save_stack+0x1e/0x40
 __kasan_slab_alloc+0x66/0x80
 kmem_cache_alloc+0x1b1/0x490
 __kernfs_new_node+0xd4/0x8b0
 kernfs_new_node+0x93/0x120
 __kernfs_create_file+0x51/0x350
 cgroup_addrm_files+0x3e2/0x9d0
 css_populate_dir+0x19b/0x450
 cgroup_apply_control_enable+0x3ae/0xa40
 cgroup_mkdir+0x824/0x11f0
 kernfs_iop_mkdir+0x149/0x1d0
 vfs_mkdir+0x417/0x6a0
 do_mkdirat+0x17b/0x2e0
 __x64_sys_mkdir+0xf2/0x140
 do_syscall_64+0x3b/0x90
 entry_SYSCALL_64_after_hwframe+0x46/0xb0

Freed by task 83:
 kasan_save_stack+0x1e/0x40
 kasan_set_track+0x21/0x30
 kasan_set_free_info+0x20/0x30
 __kasan_slab_free+0x108/0x190
 kmem_cache_free+0xfb/0x600
 kernfs_put.part.0+0x2c7/0x540
 kernfs_put+0x42/0x50
 kernfs_notify_workfn+0x417/0x560
 process_one_work+0xa0f/0x1690
 worker_thread+0x637/0x1250
 kthread+0x2ed/0x3a0
 ret_from_fork+0x22/0x30

The buggy address belongs to the object at ffff88803725fcb0
 which belongs to the cache kernfs_node_cache of size 168
The buggy address is located 128 bytes inside of
 168-byte region [ffff88803725fcb0, ffff88803725fd58)

The buggy address belongs to the physical page:
page:000000004c2ccff3 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x3725f
flags: 0x100000000000200(slab|node=0|zone=1)
raw: 0100000000000200 0000000000000000 dead000000000122 ffff8880080718c0
raw: 0000000000000000 0000000000110011 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88803725fc00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 fc fc
 ffff88803725fc80: fc fc fc fc fc fc fa fb fb fb fb fb fb fb fb fb
>ffff88803725fd00: fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc fc
                                     ^
 ffff88803725fd80: fc fc fc 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88803725fe00: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc
==================================================================
----------------
Code disassembly (best guess):
   0:	83 e2 07             	and    $0x7,%edx
   3:	38 d0                	cmp    %dl,%al
   5:	7f 08                	jg     0xf
   7:	84 c0                	test   %al,%al
   9:	0f 85 d5 02 00 00    	jne    0x2e4
   f:	88 5d 00             	mov    %bl,0x0(%rbp)
  12:	e8 db 3e 00 00       	callq  0x3ef2
  17:	31 ff                	xor    %edi,%edi
  19:	4c 89 f6             	mov    %r14,%rsi
  1c:	e8 91 3f 19 00       	callq  0x193fb2
  21:	4d 85 f6             	test   %r14,%r14
  24:	0f 85 76 01 00 00    	jne    0x1a0
* 2a:	e8 93 42 19 00       	callq  0x1942c2 <-- trapping instruction
  2f:	48 b8 00 00 00 00 00 	movabs $0xdffffc0000000000,%rax
  36:	fc ff df
  39:	48 03 04 24          	add    (%rsp),%rax
  3d:	48                   	rex.W
  3e:	c7                   	.byte 0xc7