------------[ cut here ]------------
refcount_t: underflow; use-after-free.
WARNING: lib/refcount.c:28 at refcount_warn_saturate+0xb2/0x110 lib/refcount.c:28, CPU#1: ktimers/1/30
Modules linked in:
CPU: 1 UID: 0 PID: 30 Comm: ktimers/1 Tainted: G             L      syzkaller #0 PREEMPT_{RT,(full)} 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/25/2026
RIP: 0010:refcount_warn_saturate+0xb2/0x110 lib/refcount.c:28
Code: 84 ee 0d 0b 67 48 0f b9 3a eb 4a e8 48 3b f8 fc 48 8d 3d 81 ee 0d 0b 67 48 0f b9 3a eb 37 e8 35 3b f8 fc 48 8d 3d 7e ee 0d 0b <67> 48 0f b9 3a eb 24 e8 22 3b f8 fc 48 8d 3d 7b ee 0d 0b 67 48 0f
RSP: 0018:ffffc90000a4fa28 EFLAGS: 00010246
RAX: ffffffff84cd687b RBX: 0000000000000003 RCX: ffff88801e2f9f40
RDX: 0000000000000100 RSI: 0000000000000000 RDI: ffffffff8fdb5700
RBP: ffffc90000a4fb30 R08: ffff88801e2f9f40 R09: 0000000000000005
R10: 0000000000000100 R11: 0000000000000004 R12: 0000000000000001
R13: 00000001000142c8 R14: ffff888035e7f820 R15: ffff888035e7f9b8
FS:  0000000000000000(0000) GS:ffff888125af2000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055556d7f14e8 CR3: 0000000026b90000 CR4: 00000000003526f0
DR0: ffffffffffffffff DR1: 00000000000001f8 DR2: 0000000000000002
DR3: ffffffffefffff15 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 call_timer_fn+0x192/0x5e0 kernel/time/timer.c:1748
 expire_timers kernel/time/timer.c:1799 [inline]
 __run_timers kernel/time/timer.c:2374 [inline]
 __run_timer_base+0x67b/0x9b0 kernel/time/timer.c:2386
 run_timer_base kernel/time/timer.c:2395 [inline]
 run_timer_softirq+0xb7/0x170 kernel/time/timer.c:2405
 handle_softirqs+0x1d9/0x6c0 kernel/softirq.c:626
 __do_softirq kernel/softirq.c:660 [inline]
 run_ktimerd+0x69/0x100 kernel/softirq.c:1155
 smpboot_thread_fn+0x57c/0xa80 kernel/smpboot.c:160
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 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:	84 ee                	test   %ch,%dh
   2:	0d 0b 67 48 0f       	or     $0xf48670b,%eax
   7:	b9 3a eb 4a e8       	mov    $0xe84aeb3a,%ecx
   c:	48 3b f8             	cmp    %rax,%rdi
   f:	fc                   	cld
  10:	48 8d 3d 81 ee 0d 0b 	lea    0xb0dee81(%rip),%rdi        # 0xb0dee98
  17:	67 48 0f b9 3a       	ud1    (%edx),%rdi
  1c:	eb 37                	jmp    0x55
  1e:	e8 35 3b f8 fc       	call   0xfcf83b58
  23:	48 8d 3d 7e ee 0d 0b 	lea    0xb0dee7e(%rip),%rdi        # 0xb0deea8
* 2a:	67 48 0f b9 3a       	ud1    (%edx),%rdi <-- trapping instruction
  2f:	eb 24                	jmp    0x55
  31:	e8 22 3b f8 fc       	call   0xfcf83b58
  36:	48 8d 3d 7b ee 0d 0b 	lea    0xb0dee7b(%rip),%rdi        # 0xb0deeb8
  3d:	67                   	addr32
  3e:	48                   	rex.W
  3f:	0f                   	.byte 0xf