------------[ cut here ]------------
refcount_t: underflow; use-after-free.
WARNING: lib/refcount.c:28 at refcount_warn_saturate+0xb2/0x110 lib/refcount.c:28, CPU#0: syz.5.6508/1328
Modules linked in:
CPU: 0 UID: 0 PID: 1328 Comm: syz.5.6508 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:refcount_warn_saturate+0xb2/0x110 lib/refcount.c:28
Code: 14 a6 85 0b 67 48 0f b9 3a eb 4a e8 88 1d 0e fd 48 8d 3d 11 a6 85 0b 67 48 0f b9 3a eb 37 e8 75 1d 0e fd 48 8d 3d 0e a6 85 0b <67> 48 0f b9 3a eb 24 e8 62 1d 0e fd 48 8d 3d 0b a6 85 0b 67 48 0f
RSP: 0018:ffffc90000007ca8 EFLAGS: 00010246
RAX: ffffffff84b8540b RBX: 0000000000000003 RCX: ffff888021f35d00
RDX: 0000000000000100 RSI: ffffffff8f123700 RDI: ffffffff903dfa20
RBP: ffffc90000007db0 R08: ffff888021f35d00 R09: 0000000000000005
R10: 0000000000000004 R11: 0000000000000100 R12: 0000000000000000
R13: 0000000100019c88 R14: ffff88807e033820 R15: ffff88807e0339b8
FS:  00007fe079fe56c0(0000) GS:ffff888125226000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f7c69a6937e CR3: 00000000341f8000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000200000000300 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 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+0x652/0x8b0 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+0x225/0x840 kernel/softirq.c:622
 do_softirq+0x76/0xd0 kernel/softirq.c:523
 </IRQ>
 <TASK>
 __local_bh_enable_ip+0xf8/0x130 kernel/softirq.c:450
 sock_orphan include/net/sock.h:2142 [inline]
 sk_common_release+0x14a/0x310 net/core/sock.c:4062
 pep_sock_close+0x79/0x5b0 net/phonet/pep.c:755
 pn_socket_release+0x9b/0xc0 net/phonet/socket.c:34
 __sock_release net/socket.c:710 [inline]
 sock_close+0xad/0x220 net/socket.c:1501
 __fput+0x418/0xa50 fs/file_table.c:512
 fput_close_sync+0x11f/0x240 fs/file_table.c:617
 __do_sys_close fs/open.c:1511 [inline]
 __se_sys_close fs/open.c:1496 [inline]
 __x64_sys_close+0x7e/0x110 fs/open.c:1496
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fe07919ce59
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fe079fe5028 EFLAGS: 00000246 ORIG_RAX: 0000000000000003
RAX: ffffffffffffffda RBX: 00007fe079416180 RCX: 00007fe07919ce59
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 00007fe079232e6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fe079416218 R14: 00007fe079416180 R15: 00007ffef587dfc8
 </TASK>
----------------
Code disassembly (best guess):
   0:	14 a6                	adc    $0xa6,%al
   2:	85 0b                	test   %ecx,(%rbx)
   4:	67 48 0f b9 3a       	ud1    (%edx),%rdi
   9:	eb 4a                	jmp    0x55
   b:	e8 88 1d 0e fd       	call   0xfd0e1d98
  10:	48 8d 3d 11 a6 85 0b 	lea    0xb85a611(%rip),%rdi        # 0xb85a628
  17:	67 48 0f b9 3a       	ud1    (%edx),%rdi
  1c:	eb 37                	jmp    0x55
  1e:	e8 75 1d 0e fd       	call   0xfd0e1d98
  23:	48 8d 3d 0e a6 85 0b 	lea    0xb85a60e(%rip),%rdi        # 0xb85a638
* 2a:	67 48 0f b9 3a       	ud1    (%edx),%rdi <-- trapping instruction
  2f:	eb 24                	jmp    0x55
  31:	e8 62 1d 0e fd       	call   0xfd0e1d98
  36:	48 8d 3d 0b a6 85 0b 	lea    0xb85a60b(%rip),%rdi        # 0xb85a648
  3d:	67                   	addr32
  3e:	48                   	rex.W
  3f:	0f                   	.byte 0xf