------------[ cut here ]------------
refcount_t: underflow; use-after-free.
WARNING: lib/refcount.c:28 at refcount_warn_saturate+0xb2/0x110, CPU#1: swapper/1/0
Modules linked in:
CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
RIP: 0010:refcount_warn_saturate+0xb2/0x110
Code: 44 b3 89 0b 67 48 0f b9 3a eb 4a e8 b8 b0 13 fd 48 8d 3d 41 b3 89 0b 67 48 0f b9 3a eb 37 e8 a5 b0 13 fd 48 8d 3d 3e b3 89 0b <67> 48 0f b9 3a eb 24 e8 92 b0 13 fd 48 8d 3d 3b b3 89 0b 67 48 0f
RSP: 0018:ffffc90000a08c68 EFLAGS: 00010246
RAX: ffffffff84b20ecb RBX: 0000000000000003 RCX: ffff8881604f0000
RDX: 0000000000000100 RSI: ffffffff8f10f400 RDI: ffffffff903bc210
RBP: ffffc90000a08d70 R08: ffff8881604f0000 R09: 0000000000000005
R10: 0000000000000004 R11: 0000000000000100 R12: 0000000000000001
R13: 00000000ffffab7c R14: ffff8881b464d820 R15: ffff8881b464d9b8
FS:  0000000000000000(0000) GS:ffff8882a9287000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b3390eff8 CR3: 00000001bfb64000 CR4: 00000000000006f0
Call Trace:
 <IRQ>
 call_timer_fn+0x192/0x5e0
 __run_timer_base+0x652/0x8b0
 run_timer_softirq+0xb7/0x170
 handle_softirqs+0x22a/0x840
 __irq_exit_rcu+0xca/0x220
 irq_exit_rcu+0x9/0x30
 sysvec_apic_timer_interrupt+0xa6/0xc0
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20
RIP: 0010:pv_native_safe_halt+0xf/0x20
Code: cb 7c 02 e9 93 f6 02 00 cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa eb 07 0f 00 2d 53 b1 1f 00 fb f4 <c3> cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90
RSP: 0018:ffffc90000197e20 EFLAGS: 00000202
RAX: 0000000000040461 RBX: ffffffff819a91ea RCX: 0000000080000001
RDX: 0000000000000001 RSI: ffffffff8dfaaf26 RDI: ffffffff8c28ade0
RBP: ffffc90000197f10 R08: ffff88823c6339db R09: 1ffff110478c673b
R10: dffffc0000000000 R11: ffffed10478c673c R12: 0000000000000001
R13: 1ffff1102c09e000 R14: 0000000000000001 R15: 1ffff1102c09e000
 default_idle+0x9/0x20
 default_idle_call+0x72/0xb0
 do_idle+0x36a/0x5f0
 cpu_startup_entry+0x43/0x60
 start_secondary+0x101/0x110
 common_startup_64+0x13e/0x147
 </TASK>
