------------[ cut here ]------------
refcount_t: underflow; use-after-free.
WARNING: lib/refcount.c:28 at refcount_warn_saturate+0xf4/0x130 lib/refcount.c:28, CPU#0: kworker/0:3/14135
Modules linked in:
CPU: 0 UID: 0 PID: 14135 Comm: kworker/0:3 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
Workqueue: mm_percpu_wq vmstat_update
RIP: 0010:refcount_warn_saturate+0xf4/0x130 lib/refcount.c:28
Code: fc e8 b0 12 09 fd 48 8d 3d d9 86 06 0c 67 48 0f b9 3a e8 9f 12 09 fd 5b 5d e9 a3 f4 0f fc e8 93 12 09 fd 48 8d 3d cc 86 06 0c <67> 48 0f b9 3a e8 82 12 09 fd 5b 5d e9 86 f4 0f fc e8 76 12 09 fd
RSP: 0018:ffffc90000007c28 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff88804cc3e820 RCX: ffffffff85004bdb
RDX: ffff88802bf51f00 RSI: ffffffff85004c6d RDI: ffffffff9106d340
RBP: 0000000000000003 R08: 0000000000000005 R09: 0000000000000004
R10: 0000000000000003 R11: 0000000000000000 R12: ffff88804cc3e820
R13: 1ffff92000000f8e R14: ffffffff8ad26b20 R15: 0000000000000001
FS:  0000000000000000(0000) GS:ffff8881240e1000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fa9e6018375 CR3: 000000007c9e2000 CR4: 0000000000350ef0
Call Trace:
 <IRQ>
 __refcount_sub_and_test include/linux/refcount.h:400 [inline]
 __refcount_dec_and_test include/linux/refcount.h:432 [inline]
 refcount_dec_and_test include/linux/refcount.h:450 [inline]
 sctp_transport_put+0x134/0x180 net/sctp/transport.c:476
 call_timer_fn+0x19a/0x610 kernel/time/timer.c:1748
 expire_timers kernel/time/timer.c:1799 [inline]
 __run_timers+0x757/0xb00 kernel/time/timer.c:2374
 __run_timer_base kernel/time/timer.c:2386 [inline]
 __run_timer_base kernel/time/timer.c:2378 [inline]
 run_timer_base+0x114/0x190 kernel/time/timer.c:2395
 run_timer_softirq+0x1a/0x50 kernel/time/timer.c:2405
 handle_softirqs+0x1ea/0x9b0 kernel/softirq.c:622
 __do_softirq kernel/softirq.c:656 [inline]
 invoke_softirq kernel/softirq.c:496 [inline]
 __irq_exit_rcu+0x162/0x210 kernel/softirq.c:735
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:752
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline]
 sysvec_apic_timer_interrupt+0xa3/0xc0 arch/x86/kernel/apic/apic.c:1062
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:179 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0x31/0x80 kernel/locking/spinlock.c:198
Code: f5 53 48 8b 74 24 10 48 89 fb 48 83 c7 18 e8 96 8e 46 f6 48 89 df e8 1e de 46 f6 f7 c5 00 02 00 00 75 23 9c 58 f6 c4 02 75 37 <bf> 01 00 00 00 e8 25 ef 35 f6 65 8b 05 ee 88 95 08 85 c0 74 16 5b
RSP: 0018:ffffc90003f97990 EFLAGS: 00000246
RAX: 0000000000000002 RBX: ffff88813fffbf40 RCX: 0000000000000040
RDX: 0000000000000000 RSI: ffffffff8df6609b RDI: ffffffff8c1e8f80
RBP: 0000000000000287 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: dffffc0000000000 R12: 000000000000003f
R13: 000000000000003f R14: ffff88813fffb940 R15: 00000000000014c6
 decay_pcp_high+0x130/0x180 mm/page_alloc.c:2587
 refresh_cpu_vm_stats+0x2f5/0x8b0 mm/vmstat.c:830
 vmstat_update+0x12/0xb0 mm/vmstat.c:2039
 process_one_work+0xa23/0x1940 kernel/workqueue.c:3322
 process_scheduled_works kernel/workqueue.c:3405 [inline]
 worker_thread+0x5ef/0xe50 kernel/workqueue.c:3486
 kthread+0x370/0x450 kernel/kthread.c:436
 ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
----------------
Code disassembly (best guess):
   0:	fc                   	cld
   1:	e8 b0 12 09 fd       	call   0xfd0912b6
   6:	48 8d 3d d9 86 06 0c 	lea    0xc0686d9(%rip),%rdi        # 0xc0686e6
   d:	67 48 0f b9 3a       	ud1    (%edx),%rdi
  12:	e8 9f 12 09 fd       	call   0xfd0912b6
  17:	5b                   	pop    %rbx
  18:	5d                   	pop    %rbp
  19:	e9 a3 f4 0f fc       	jmp    0xfc0ff4c1
  1e:	e8 93 12 09 fd       	call   0xfd0912b6
  23:	48 8d 3d cc 86 06 0c 	lea    0xc0686cc(%rip),%rdi        # 0xc0686f6
* 2a:	67 48 0f b9 3a       	ud1    (%edx),%rdi <-- trapping instruction
  2f:	e8 82 12 09 fd       	call   0xfd0912b6
  34:	5b                   	pop    %rbx
  35:	5d                   	pop    %rbp
  36:	e9 86 f4 0f fc       	jmp    0xfc0ff4c1
  3b:	e8 76 12 09 fd       	call   0xfd0912b6