------------[ cut here ]------------ percpu ref (css_release) <= 0 (-2453) 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: 7ffffffffffff66a R08: 0000000000000001 R09: ffffed100d9c4801 R10: 0000000000000000 R11: 0000000000000001 R12: ffff88800dbc4500 R13: ffff88800dbc4520 R14: 0000000000000002 R15: 0000000000000003 FS: 0000000000000000(0000) GS:ffff8880e55dd000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f6ea5f8d8e8 CR3: 000000000ad26000 CR4: 0000000000350ef0 Call Trace: rcu_core+0x7c8/0x1800 handle_softirqs+0x1b1/0x770 __irq_exit_rcu+0xc4/0x100 irq_exit_rcu+0x9/0x20 sysvec_apic_timer_interrupt+0x70/0x80 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 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: 00000202 RAX: 00000000003ae229 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 irq event stamp: 3859614 hardirqs last enabled at (3859622): [] __up_console_sem+0x78/0x80 hardirqs last disabled at (3859633): [] __up_console_sem+0x5d/0x80 softirqs last enabled at (3858960): [] handle_softirqs+0x50c/0x770 softirqs last disabled at (3858987): [] __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 ffff88800dbc4500 pointer offset 0 size 64 UDC core: USB Raw Gadget: couldn't find an available UDC or it's busy 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 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 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 misc raw-gadget: fail, usb_gadget_register_driver returned -16 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: 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