------------[ cut here ]------------
kernfs_put: syz0/memory.events.local: released with incorrect active_ref 0
WARNING: CPU: 0 PID: 6 at fs/kernfs/dir.c:531 kernfs_put.part.0+0x433/0x540
Modules linked in:
CPU: 0 PID: 6 Comm: kworker/0:0 Not tainted 5.19.0-rc5-next-20220705 #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_put.part.0+0x433/0x540
Code: 03 80 3c 18 00 0f 85 ea 00 00 00 4d 8b 7d 38 e8 73 0b a7 ff 48 8b 14 24 44 89 f1 4c 89 fe 48 c7 c7 e0 58 72 84 e8 93 ac 6c 02 <0f> 0b e9 b9 fc ff ff 48 89 ef e8 0e b3 d9 ff e9 c1 fd ff ff e8 04
RSP: 0018:ffff888008217bd8 EFLAGS: 00010286
RAX: 0000000000000000 RBX: dffffc0000000000 RCX: 0000000000000000
RDX: ffff888008201ac0 RSI: ffffffff812bd348 RDI: ffffed1001042f6d
RBP: ffff88801808c948 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000001 R12: ffff88801808c910
R13: ffff888041652828 R14: 0000000000000000 R15: ffff888014bc6028
FS:  0000000000000000(0000) GS:ffff88806ce00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020060000 CR3: 000000000df0c000 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: 427369
hardirqs last  enabled at (427379): [<ffffffff812b62a8>] __up_console_sem+0x78/0x80
hardirqs last disabled at (427390): [<ffffffff812b628d>] __up_console_sem+0x5d/0x80
softirqs last  enabled at (426964): [<ffffffff81306195>] srcu_invoke_callbacks+0x1e5/0x3a0
softirqs last disabled at (426960): [<ffffffff81306165>] srcu_invoke_callbacks+0x1b5/0x3a0
---[ end trace 0000000000000000 ]---
==================================================================
BUG: KASAN: use-after-free in llist_del_first+0x89/0xa0
Read of size 8 at addr ffff88801808c990 by task kworker/0:0/6

CPU: 0 PID: 6 Comm: kworker/0:0 Tainted: G        W          5.19.0-rc5-next-20220705 #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 296:
 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 6:
 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 ffff88801808c910
 which belongs to the cache kernfs_node_cache of size 168
The buggy address is located 128 bytes inside of
 168-byte region [ffff88801808c910, ffff88801808c9b8)

The buggy address belongs to the physical page:
page:00000000f2428db6 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1808c
flags: 0x100000000000200(slab|node=0|zone=1)
raw: 0100000000000200 0000000000000000 dead000000000122 ffff8880080358c0
raw: 0000000000000000 0000000000110011 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88801808c880: fb fb fb fb fb fb fb fb fb fb fc fc fc fc fc fc
 ffff88801808c900: fc fc fa fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88801808c980: fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc 00
                         ^
 ffff88801808ca00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88801808ca80: 00 00 00 00 fc fc fc fc fc fc fc fc 00 00 00 00
==================================================================
loop5: detected capacity change from 0 to 40