------------[ 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 01/13/2026
RIP: 0010:refcount_warn_saturate+0xb2/0x110 lib/refcount.c:28
Code: 24 5e a9 0a 67 48 0f b9 3a eb 4a e8 38 4e 39 fd 48 8d 3d 21 5e a9 0a 67 48 0f b9 3a eb 37 e8 25 4e 39 fd 48 8d 3d 1e 5e a9 0a <67> 48 0f b9 3a eb 24 e8 12 4e 39 fd 48 8d 3d 1b 5e a9 0a 67 48 0f
RSP: 0018:ffffc90000a3f8c8 EFLAGS: 00010246
RAX: ffffffff8488113b RBX: 0000000000000003 RCX: ffff88801cae1e40
RDX: 0000000000000100 RSI: 0000000000000000 RDI: ffffffff8f316f60
RBP: 0000000000000000 R08: ffff88801cae1e40 R09: 0000000000000005
R10: 0000000000000100 R11: 0000000000000004 R12: ffffffff99695001
R13: ffff8880284e4000 R14: ffff8880284e4080 R15: ffff8880284e4070
FS:  0000000000000000(0000) GS:ffff8881268fc000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005555709e0a28 CR3: 000000000d7b4000 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+0x192/0x5a0 kernel/time/timer.c:1748
 expire_timers kernel/time/timer.c:1799 [inline]
 __run_timers kernel/time/timer.c:2373 [inline]
 __run_timer_base+0x6a3/0x9f0 kernel/time/timer.c:2385
 run_timer_base kernel/time/timer.c:2394 [inline]
 run_timer_softirq+0x67/0x170 kernel/time/timer.c:2402
 handle_softirqs+0x1de/0x640 kernel/softirq.c:622
 __do_softirq kernel/softirq.c:656 [inline]
 run_ktimerd+0x69/0x100 kernel/softirq.c:1138
 smpboot_thread_fn+0x541/0xa50 kernel/smpboot.c:160
 kthread+0x726/0x8b0 kernel/kthread.c:463
 ret_from_fork+0x51b/0xa40 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:	24 5e                	and    $0x5e,%al
   2:	a9 0a 67 48 0f       	test   $0xf48670a,%eax
   7:	b9 3a eb 4a e8       	mov    $0xe84aeb3a,%ecx
   c:	38 4e 39             	cmp    %cl,0x39(%rsi)
   f:	fd                   	std
  10:	48 8d 3d 21 5e a9 0a 	lea    0xaa95e21(%rip),%rdi        # 0xaa95e38
  17:	67 48 0f b9 3a       	ud1    (%edx),%rdi
  1c:	eb 37                	jmp    0x55
  1e:	e8 25 4e 39 fd       	call   0xfd394e48
  23:	48 8d 3d 1e 5e a9 0a 	lea    0xaa95e1e(%rip),%rdi        # 0xaa95e48
* 2a:	67 48 0f b9 3a       	ud1    (%edx),%rdi <-- trapping instruction
  2f:	eb 24                	jmp    0x55
  31:	e8 12 4e 39 fd       	call   0xfd394e48
  36:	48 8d 3d 1b 5e a9 0a 	lea    0xaa95e1b(%rip),%rdi        # 0xaa95e58
  3d:	67                   	addr32
  3e:	48                   	rex.W
  3f:	0f                   	.byte 0xf