------------[ 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/1/29
Modules linked in:
CPU: 1 UID: 0 PID: 29 Comm: ktimers/1 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:refcount_warn_saturate+0xb2/0x110 lib/refcount.c:28
Code: 14 69 66 0a 67 48 0f b9 3a eb 4a e8 b8 c8 41 fd 48 8d 3d 11 69 66 0a 67 48 0f b9 3a eb 37 e8 a5 c8 41 fd 48 8d 3d 0e 69 66 0a <67> 48 0f b9 3a eb 24 e8 92 c8 41 fd 48 8d 3d 0b 69 66 0a 67 48 0f
RSP: 0018:ffffc90000a3f788 EFLAGS: 00010246
RAX: ffffffff847e99eb RBX: 0000000000000003 RCX: ffff88801bea1e40
RDX: 0000000000000100 RSI: 0000000000000000 RDI: ffffffff8ee50300
RBP: 0000000000000000 R08: ffff88801bea1e40 R09: 0000000000000005
R10: 0000000000000100 R11: 0000000000000004 R12: ffffffff9918d901
R13: ffff88803a44c000 R14: ffff88803a44c080 R15: ffff88803a44c070
FS:  0000000000000000(0000) GS:ffff888126e03000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 0000000029d1e000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 __inet_csk_reqsk_queue_drop+0x2c3/0x340 net/ipv4/inet_connection_sock.c:1012
 reqsk_timer_handler+0x7c8/0xcf0 net/ipv4/inet_connection_sock.c:1141
 call_timer_fn+0x16e/0x590 kernel/time/timer.c:1748
 expire_timers kernel/time/timer.c:1799 [inline]
 __run_timers kernel/time/timer.c:2373 [inline]
 __run_timer_base+0x648/0x970 kernel/time/timer.c:2385
 run_timer_base kernel/time/timer.c:2394 [inline]
 run_timer_softirq+0x67/0x180 kernel/time/timer.c:2402
 handle_softirqs+0x226/0x6d0 kernel/softirq.c:622
 __do_softirq kernel/softirq.c:656 [inline]
 run_ktimerd+0xcf/0x190 kernel/softirq.c:1138
 smpboot_thread_fn+0x542/0xa60 kernel/smpboot.c:160
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
 </TASK>
----------------
Code disassembly (best guess):
   0:	14 69                	adc    $0x69,%al
   2:	66 0a 67 48          	data16 or 0x48(%rdi),%ah
   6:	0f b9 3a             	ud1    (%rdx),%edi
   9:	eb 4a                	jmp    0x55
   b:	e8 b8 c8 41 fd       	call   0xfd41c8c8
  10:	48 8d 3d 11 69 66 0a 	lea    0xa666911(%rip),%rdi        # 0xa666928
  17:	67 48 0f b9 3a       	ud1    (%edx),%rdi
  1c:	eb 37                	jmp    0x55
  1e:	e8 a5 c8 41 fd       	call   0xfd41c8c8
  23:	48 8d 3d 0e 69 66 0a 	lea    0xa66690e(%rip),%rdi        # 0xa666938
* 2a:	67 48 0f b9 3a       	ud1    (%edx),%rdi <-- trapping instruction
  2f:	eb 24                	jmp    0x55
  31:	e8 92 c8 41 fd       	call   0xfd41c8c8
  36:	48 8d 3d 0b 69 66 0a 	lea    0xa66690b(%rip),%rdi        # 0xa666948
  3d:	67                   	addr32
  3e:	48                   	rex.W
  3f:	0f                   	.byte 0xf