__x64_sys_io_uring_setup+0xc8/0x170
 do_syscall_64+0xbf/0x360
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
------------[ cut here ]------------
percpu ref (free_ioctx_users) <= 0 (-4294967295) after switching to atomic
WARNING: lib/percpu-refcount.c:197 at percpu_ref_switch_to_atomic_rcu+0x3cc/0x480, CPU#1: syz-executor.3/284
Modules linked in:
CPU: 1 UID: 0 PID: 284 Comm: syz-executor.3 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:ffff88806cf08e20 EFLAGS: 00010286
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff8139de70
RDX: ffff888016a29b80 RSI: ffffffff8139de7e RDI: 0000000000000001
RBP: 7fffffff00000000 R08: 0000000000000001 R09: ffffed100d9e4801
R10: 0000000000000000 R11: 0000000000000001 R12: ffff88800cb3eb00
R13: ffff88800cb3eb20 R14: 0000000000000002 R15: 0000000000000003
FS:  000055558813b400(0000) GS:ffff8880e56dd000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f425a3a3780 CR3: 000000003984e000 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:finish_task_switch.isra.0+0x20f/0x840
Code: 4c 89 ff 48 c7 03 00 00 00 00 e8 dc ee 76 03 4d 85 e4 75 ba 4c 89 ff e8 3f d5 76 03 e8 fa 1e 35 00 fb 65 48 8b 1d 99 22 3d 06 <48> 8d bb f0 14 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1
RSP: 0018:ffff88801b07fac0 EFLAGS: 00000202
RAX: 000000000002adab RBX: ffff888016a29b80 RCX: ffffffff817c2b86
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff81470d76
RBP: ffff88801b07fb00 R08: 0000000000000001 R09: 0000000000000001
R10: ffffffff8643ac57 R11: 0000000000000001 R12: ffff88806cf36ed8
R13: ffff888033b88000 R14: ffff888033b88000 R15: ffff88806cf36ec0
 __schedule+0xe86/0x3590
 schedule+0xdb/0x390
 do_nanosleep+0x15e/0x560
kmemleak: Found object by alias at 0x607f1a629fa4
CPU: 0 UID: 0 PID: 4016 Comm: iou-sqp-4007 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
 percpu_counter_destroy_many+0x188/0x2b0
 __io_uring_free+0x134/0x1e0
 io_uring_cancel_generic+0x814/0x960
 io_sq_thread+0xd50/0x1b00
 ret_from_fork+0x34b/0x430
 ret_from_fork_asm+0x1a/0x30
 </TASK>
kmemleak: Object (percpu) 0x607f1a629fa0 (size 8):
kmemleak:   comm "syz-executor.6", pid 4007, jiffies 4294798730
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
kmemleak: Automatic memory scanning thread ended
 hrtimer_nanosleep+0x13a/0x340
 common_nsleep+0xaa/0xd0
 __x64_sys_clock_nanosleep+0x331/0x470
 do_syscall_64+0xbf/0x360
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f829b3dd8e1
Code: 24 0c 89 3c 24 48 89 4c 24 18 e8 aa e7 ff ff 4c 8b 54 24 18 48 8b 54 24 10 41 89 c0 8b 74 24 0c 8b 3c 24 b8 e6 00 00 00 0f 05 <44> 89 c7 48 89 04 24 e8 e3 e7 ff ff 48 8b 04 24 eb 97 66 2e 0f 1f
RSP: 002b:00007ffd968348f0 EFLAGS: 00000293 ORIG_RAX: 00000000000000e6
RAX: ffffffffffffffda RBX: 000000000000000e RCX: 00007f829b3dd8e1
RDX: 00007ffd96834930 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007ffd968349bc R08: 0000000000000000 R09: 00007f829b4a8000
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000032
R13: 000000000002037a R14: 0000000000000010 R15: 00007ffd96834a20
 </TASK>
irq event stamp: 176470
hardirqs last  enabled at (176480): [<ffffffff81541b18>] __up_console_sem+0x78/0x80
hardirqs last disabled at (176489): [<ffffffff81541afd>] __up_console_sem+0x5d/0x80
softirqs last  enabled at (173926): [<ffffffff813bafcc>] handle_softirqs+0x50c/0x770
softirqs last disabled at (175533): [<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 ffff88800cb3eb00 pointer offset 0 size 64
UDC core: USB Raw Gadget: couldn't find an available UDC or it's busy
misc raw-gadget: fail, usb_gadget_register_driver returned -16
----------------
Code disassembly (best guess):
   0:	4c 89 ff             	mov    %r15,%rdi
   3:	48 c7 03 00 00 00 00 	movq   $0x0,(%rbx)
   a:	e8 dc ee 76 03       	callq  0x376eeeb
   f:	4d 85 e4             	test   %r12,%r12
  12:	75 ba                	jne    0xffffffce
  14:	4c 89 ff             	mov    %r15,%rdi
  17:	e8 3f d5 76 03       	callq  0x376d55b
  1c:	e8 fa 1e 35 00       	callq  0x351f1b
  21:	fb                   	sti
  22:	65 48 8b 1d 99 22 3d 	mov    %gs:0x63d2299(%rip),%rbx        # 0x63d22c3
  29:	06
* 2a:	48 8d bb f0 14 00 00 	lea    0x14f0(%rbx),%rdi <-- trapping instruction
  31:	48 b8 00 00 00 00 00 	movabs $0xdffffc0000000000,%rax
  38:	fc ff df
  3b:	48 89 fa             	mov    %rdi,%rdx
  3e:	48                   	rex.W
  3f:	c1                   	.byte 0xc1