------------[ cut here ]------------ percpu ref (css_release) <= 0 (-1) after switching to atomic WARNING: lib/percpu-refcount.c:197 at percpu_ref_switch_to_atomic_rcu+0x3cc/0x480, CPU#1: ksoftirqd/1/22 Modules linked in: CPU: 1 UID: 0 PID: 22 Comm: ksoftirqd/1 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:ffff888009747c70 EFLAGS: 00010282 RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff8139de70 RDX: ffff88800972b700 RSI: ffffffff8139de7e RDI: 0000000000000001 RBP: 7fffffffffffffff R08: 0000000000000001 R09: ffffed100d9e4801 R10: 0000000000000000 R11: 0000000000000001 R12: ffff8880206dd000 R13: ffff8880206dd020 R14: 0000000000000002 R15: 0000000000000003 FS: 0000000000000000(0000) GS:ffff8880e56dd000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffff7b1a000 CR3: 000000000c2d6000 CR4: 0000000000350ef0 Call Trace: rcu_core+0x7c8/0x1800 handle_softirqs+0x1b1/0x770 run_ksoftirqd+0x2e/0x60 smpboot_thread_fn+0x41d/0x9d0 kthread+0x3c8/0x740 ret_from_fork+0x34b/0x430 ret_from_fork_asm+0x1a/0x30 irq event stamp: 7340844 hardirqs last enabled at (7340852): [] __up_console_sem+0x78/0x80 hardirqs last disabled at (7340861): [] __up_console_sem+0x5d/0x80 softirqs last enabled at (7340446): [] handle_softirqs+0x50c/0x770 softirqs last disabled at (7340451): [] run_ksoftirqd+0x2e/0x60 ---[ end trace 0000000000000000 ]--- percpu_ref_switch_to_atomic_rcu: percpu_ref_switch_to_atomic_rcu(): percpu_ref underflow slab kmalloc-64 start ffff8880206dd000 pointer offset 0 size 64 percpu_ref_switch_to_atomic_rcu: percpu_ref_switch_to_atomic_rcu(): percpu_ref underflow slab kmalloc-64 start ffff88800eb92980 pointer offset 0 size 64