------------[ 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: syz-executor/9987
Modules linked in:
CPU: 1 UID: 0 PID: 9987 Comm: syz-executor Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
RIP: 0010:refcount_warn_saturate+0xb2/0x110 lib/refcount.c:28
Code: 54 66 89 0b 67 48 0f b9 3a eb 4a e8 28 5d 13 fd 48 8d 3d 51 66 89 0b 67 48 0f b9 3a eb 37 e8 15 5d 13 fd 48 8d 3d 4e 66 89 0b <67> 48 0f b9 3a eb 24 e8 02 5d 13 fd 48 8d 3d 4b 66 89 0b 67 48 0f
RSP: 0018:ffffc90000a08c68 EFLAGS: 00010246
RAX: ffffffff84b258eb RBX: 0000000000000003 RCX: ffff88802e689ec0
RDX: 0000000000000100 RSI: ffffffff8f110200 RDI: ffffffff903bbf40
RBP: ffffc90000a08d70 R08: ffff88802e689ec0 R09: 0000000000000005
R10: 0000000000000004 R11: 0000000000000100 R12: 0000000000000001
R13: 0000000100003aff R14: ffff888076bd4820 R15: ffff888076bd4968
FS:  0000555565399500(0000) GS:ffff888125387000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000020000087b000 CR3: 000000007a868000 CR4: 00000000003526f0
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+0x22a/0x840 kernel/softirq.c:622
 __do_softirq kernel/softirq.c:656 [inline]
 invoke_softirq kernel/softirq.c:496 [inline]
 __irq_exit_rcu+0xca/0x220 kernel/softirq.c:735
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:752
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1061 [inline]
 sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1061
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:finish_task_switch+0x427/0xbe0 kernel/sched/core.c:5245
Code: 41 c7 84 24 e0 0d 00 00 00 00 00 00 0f 1f 44 00 00 49 83 c4 48 4c 89 e7 e8 16 28 17 0a e8 31 fc 38 00 fb 49 8d bd b0 16 00 00 <48> 89 f8 48 c1 e8 03 42 0f b6 04 38 84 c0 0f 85 7b 03 00 00 41 80
RSP: 0018:ffffc9001dddf930 EFLAGS: 00000206
RAX: 00000000000f7e27 RBX: 1ffff110170e7784 RCX: 0000000080000001
RDX: 0000000000000000 RSI: ffffffff8dfad387 RDI: ffff88802e68b570
RBP: ffffc9001dddf990 R08: ffffffff9030daf7 R09: 1ffffffff2061b5e
R10: dffffc0000000000 R11: fffffbfff2061b5f R12: ffff8880b873ae88
R13: ffff88802e689ec0 R14: ffff88801dad8000 R15: dffffc0000000000
 context_switch kernel/sched/core.c:5391 [inline]
 __schedule+0x1829/0x5740 kernel/sched/core.c:7189
 __schedule_loop kernel/sched/core.c:7268 [inline]
 schedule+0x164/0x360 kernel/sched/core.c:7283
 do_nanosleep+0x1c2/0x620 kernel/time/hrtimer.c:2293
 hrtimer_nanosleep+0x18f/0x3a0 kernel/time/hrtimer.c:2339
 __do_sys_clock_nanosleep kernel/time/posix-timers.c:1391 [inline]
 __se_sys_clock_nanosleep+0x35b/0x3b0 kernel/time/posix-timers.c:1368
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f161895d68e
Code: 08 0f 85 a5 a8 ff ff 49 89 fb 48 89 f0 48 89 d7 48 89 ce 4c 89 c2 4d 89 ca 4c 8b 44 24 08 4c 8b 4c 24 10 4c 89 5c 24 08 0f 05 <c3> 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 80 00 00 00 00 48 83 ec 08
RSP: 002b:00007f1618d3fd28 EFLAGS: 00000246 ORIG_RAX: 00000000000000e6
RAX: ffffffffffffffda RBX: 0000555565399500 RCX: 00007f161895d68e
RDX: 00007f1618d3fd80 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f1618d3fdec R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000001388
R13: 00000000000927c0 R14: 000000000006ddb9 R15: 00007f1618d3fe40
 </TASK>
----------------
Code disassembly (best guess):
   0:	54                   	push   %rsp
   1:	66 89 0b             	mov    %cx,(%rbx)
   4:	67 48 0f b9 3a       	ud1    (%edx),%rdi
   9:	eb 4a                	jmp    0x55
   b:	e8 28 5d 13 fd       	call   0xfd135d38
  10:	48 8d 3d 51 66 89 0b 	lea    0xb896651(%rip),%rdi        # 0xb896668
  17:	67 48 0f b9 3a       	ud1    (%edx),%rdi
  1c:	eb 37                	jmp    0x55
  1e:	e8 15 5d 13 fd       	call   0xfd135d38
  23:	48 8d 3d 4e 66 89 0b 	lea    0xb89664e(%rip),%rdi        # 0xb896678
* 2a:	67 48 0f b9 3a       	ud1    (%edx),%rdi <-- trapping instruction
  2f:	eb 24                	jmp    0x55
  31:	e8 02 5d 13 fd       	call   0xfd135d38
  36:	48 8d 3d 4b 66 89 0b 	lea    0xb89664b(%rip),%rdi        # 0xb896688
  3d:	67                   	addr32
  3e:	48                   	rex.W
  3f:	0f                   	.byte 0xf