------------[ cut here ]------------ percpu ref (free_ioctx_reqs) <= 0 (0) after switching to atomic WARNING: lib/percpu-refcount.c:197 at percpu_ref_switch_to_atomic_rcu+0x3cc/0x480, CPU#0: syz-executor.0/9128 Modules linked in: CPU: 0 UID: 0 PID: 9128 Comm: syz-executor.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: ffff888018e59b80 RSI: ffffffff8139de7e RDI: 0000000000000001 RBP: 8000000000000000 R08: 0000000000000001 R09: ffffed100d9c4801 R10: 0000000000000000 R11: 0000000000000001 R12: ffff88803cf7ef80 R13: ffff88803cf7efa0 R14: 0000000000000002 R15: 0000000000000003 FS: 0000000000000000(0000) GS:ffff8880e55dd000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b2ce26000 CR3: 000000000c9c4000 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:__kasan_check_write+0x8/0x20 Code: f0 ff ff 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 48 8b 0c 24 <89> f6 ba 01 00 00 00 e9 8c f0 ff ff 66 66 2e 0f 1f 84 00 00 00 00 RSP: 0018:ffff88803c307620 EFLAGS: 00000293 RAX: 0000000000000000 RBX: ffffea00005b48c0 RCX: ffffffff81a280ec RDX: ffff888018e59b80 RSI: 0000000000000004 RDI: ffffea00005b48f0 RBP: 0000000000000001 R08: 0000000000000000 R09: fffff940000b6918 R10: 0000000000000000 R11: 0000000000000001 R12: ffffea00005b48c0 R13: 0000000000000000 R14: ffff88800eb723c0 R15: ffffea00005b48f0 folio_remove_rmap_ptes+0x2dc/0x7c0 unmap_page_range+0x15fc/0x36d0 unmap_single_vma.constprop.0+0x153/0x230 unmap_vmas+0x1d6/0x430 exit_mmap+0x181/0xaa0 mmput+0xd5/0x390 do_exit+0x79d/0x2970 do_group_exit+0xd3/0x2a0 get_signal+0x2315/0x2340 arch_do_signal_or_restart+0x80/0x790 exit_to_user_mode_loop+0x8b/0x110 do_syscall_64+0x2f7/0x360 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fbf254f4b19 Code: Unable to access opcode bytes at 0x7fbf254f4aef. RSP: 002b:00007fbf22a28218 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 00007fbf256080e8 RCX: 00007fbf254f4b19 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fbf256080e8 RBP: 00007fbf256080e0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fbf256080ec R13: 00007fffa339d0ef R14: 00007fbf22a28300 R15: 0000000000022000 irq event stamp: 1428 hardirqs last enabled at (1436): [] __up_console_sem+0x78/0x80 hardirqs last disabled at (1445): [] __up_console_sem+0x5d/0x80 softirqs last enabled at (560): [] handle_softirqs+0x50c/0x770 softirqs last disabled at (575): [] __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 ffff88803cf7ef80 pointer offset 0 size 64 ---------------- Code disassembly (best guess): 0: f0 ff lock (bad) 2: ff 66 66 jmpq *0x66(%rsi) 5: 2e 0f 1f 84 00 00 00 nopl %cs:0x0(%rax,%rax,1) c: 00 00 e: 0f 1f 40 00 nopl 0x0(%rax) 12: 90 nop 13: 90 nop 14: 90 nop 15: 90 nop 16: 90 nop 17: 90 nop 18: 90 nop 19: 90 nop 1a: 90 nop 1b: 90 nop 1c: 90 nop 1d: 90 nop 1e: 90 nop 1f: 90 nop 20: 90 nop 21: 90 nop 22: f3 0f 1e fa endbr64 26: 48 8b 0c 24 mov (%rsp),%rcx * 2a: 89 f6 mov %esi,%esi <-- trapping instruction 2c: ba 01 00 00 00 mov $0x1,%edx 31: e9 8c f0 ff ff jmpq 0xfffff0c2 36: 66 data16 37: 66 data16 38: 2e cs 39: 0f .byte 0xf 3a: 1f (bad) 3b: 84 00 test %al,(%rax) 3d: 00 00 add %al,(%rax)