__x64_sys_mkdir+0xf3/0x140
 do_syscall_64+0xbf/0x360
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
------------[ cut here ]------------
percpu ref (css_release) <= 0 (-2423) after switching to atomic
WARNING: lib/percpu-refcount.c:197 at percpu_ref_switch_to_atomic_rcu+0x3cc/0x480, CPU#0: swapper/0/0
Modules linked in:
CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Tainted: G        W           6.17.0-rc3-next-20250829 #1 PREEMPT(voluntary) 
Tainted: [W]=WARN
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014
RIP: 0010:percpu_ref_switch_to_atomic_rcu+0x3cc/0x480
Code: 00 00 00 00 00 fc ff df 48 89 f9 48 c1 e9 03 80 3c 01 00 0f 85 9e 00 00 00 49 8b 75 e8 48 c7 c7 80 97 e2 84 e8 75 c5 e9 fe 90 <0f> 0b 90 90 e9 2b ff ff ff e8 f6 de 5f ff e9 9e fe ff ff e8 7c df
RSP: 0018:ffff88806ce08e20 EFLAGS: 00010286
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff8139de70
RDX: ffffffff85a2c8c0 RSI: ffffffff8139de7e RDI: 0000000000000001
RBP: 7ffffffffffff688 R08: 0000000000000001 R09: ffffed100d9c4801
R10: 0000000000000000 R11: 0000000000000001 R12: ffff88801fd2c180
R13: ffff88801fd2c1a0 R14: 0000000000000002 R15: 0000000000000003
FS:  0000000000000000(0000) GS:ffff8880e55dd000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffc7dc2a000 CR3: 0000000007071000 CR4: 0000000000350ef0
Call Trace:
 <IRQ>
 rcu_core+0x7c8/0x1800
 handle_softirqs+0x1b1/0x770
 __irq_exit_rcu+0xc4/0x100
 irq_exit_rcu+0x9/0x20
 sysvec_apic_timer_interrupt+0x70/0x80
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20
RIP: 0010:pv_native_safe_halt+0x1e/0x30
Code: 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 0f 1f 44 00 00 eb 0c 0f 1f 44 00 00 0f 00 2d 69 f7 09 00 0f 1f 44 00 00 fb f4 <e9> dd 83 02 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 90 90 90 90
RSP: 0018:ffffffff85a07e00 EFLAGS: 00000206
RAX: 000000000039bd53 RBX: 0000000000000000 RCX: ffffffff84bb95f7
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff814c8304
RBP: dffffc0000000000 R08: 0000000000000001 R09: ffffed100d9c630a
R10: ffff88806ce31853 R11: 0000000000000001 R12: ffffffff8643ac50
R13: 1ffffffff0b40fc7 R14: 0000000000000000 R15: 0000000000000000
 default_idle+0xe/0x20
 default_idle_call+0x6d/0xb0
 do_idle+0x344/0x490
 cpu_startup_entry+0x4f/0x60
 rest_init+0x164/0x290
 start_kernel+0x3f9/0x510
 x86_64_start_reservations+0x18/0x30
 x86_64_start_kernel+0x109/0x120
 common_startup_64+0x13e/0x148
 </TASK>
irq event stamp: 3784652
hardirqs last  enabled at (3784660): [<ffffffff81541b18>] __up_console_sem+0x78/0x80
hardirqs last disabled at (3784669): [<ffffffff81541afd>] __up_console_sem+0x5d/0x80
softirqs last  enabled at (3784014): [<ffffffff813bafcc>] handle_softirqs+0x50c/0x770
softirqs last disabled at (3784021): [<ffffffff813bb364>] __irq_exit_rcu+0xc4/0x100
---[ end trace 0000000000000000 ]---
percpu_ref_switch_to_atomic_rcu: percpu_ref_switch_to_atomic_rcu(): percpu_ref underflow slab kmalloc-64 start ffff88801fd2c180 pointer offset 0 size 64
percpu_ref_switch_to_atomic_rcu: percpu_ref_switch_to_atomic_rcu(): percpu_ref underflow slab kmalloc-64 start ffff88800bc7b580 pointer offset 0 size 64
kmemleak: Found object by alias at 0x607f1a63952c
CPU: 1 UID: 0 PID: 8171 Comm: iou-sqp-8170 Tainted: G        W           6.17.0-rc3-next-20250829 #1 PREEMPT(voluntary) 
Tainted: [W]=WARN
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0xca/0x120
 __lookup_object+0x94/0xb0
 delete_object_full+0x27/0x70
 free_percpu+0x30/0x1160
 futex_hash_free+0x38/0xc0
 mmput+0x2d3/0x390
 do_exit+0x79d/0x2970
 io_sq_thread+0xfc9/0x1b00
 ret_from_fork+0x34b/0x430
 ret_from_fork_asm+0x1a/0x30
 </TASK>
kmemleak: Object (percpu) 0x607f1a639528 (size 8):
kmemleak:   comm "syz-executor.4", pid 8173, jiffies 4295581768
kmemleak:   min_count = 1
kmemleak:   count = 0
kmemleak:   flags = 0x21
kmemleak:   checksum = 0
kmemleak:   backtrace:
 pcpu_alloc_noprof+0x87a/0x1170
 percpu_ref_init+0x37/0x400
 io_uring_setup+0x44c/0x2000
 __x64_sys_io_uring_setup+0xc8/0x170
 do_syscall_64+0xbf/0x360
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
----------------
Code disassembly (best guess):
   0:	90                   	nop
   1:	90                   	nop
   2:	90                   	nop
   3:	90                   	nop
   4:	90                   	nop
   5:	90                   	nop
   6:	90                   	nop
   7:	90                   	nop
   8:	90                   	nop
   9:	90                   	nop
   a:	90                   	nop
   b:	90                   	nop
   c:	f3 0f 1e fa          	endbr64
  10:	0f 1f 44 00 00       	nopl   0x0(%rax,%rax,1)
  15:	eb 0c                	jmp    0x23
  17:	0f 1f 44 00 00       	nopl   0x0(%rax,%rax,1)
  1c:	0f 00 2d 69 f7 09 00 	verw   0x9f769(%rip)        # 0x9f78c
  23:	0f 1f 44 00 00       	nopl   0x0(%rax,%rax,1)
  28:	fb                   	sti
  29:	f4                   	hlt
* 2a:	e9 dd 83 02 00       	jmpq   0x2840c <-- trapping instruction
  2f:	66 2e 0f 1f 84 00 00 	nopw   %cs:0x0(%rax,%rax,1)
  36:	00 00 00
  39:	0f 1f 00             	nopl   (%rax)
  3c:	90                   	nop
  3d:	90                   	nop
  3e:	90                   	nop
  3f:	90                   	nop