------------[ cut here ]------------
WARNING: ./include/linux/ns_common.h:255 at __ns_ref_put include/linux/ns_common.h:255 [inline], CPU#1: syz.3.33/6079
WARNING: ./include/linux/ns_common.h:255 at put_user_ns include/linux/user_namespace.h:189 [inline], CPU#1: syz.3.33/6079
WARNING: ./include/linux/ns_common.h:255 at delayed_free_pidns+0x118/0x150 kernel/pid_namespace.c:145, CPU#1: syz.3.33/6079
Modules linked in:
CPU: 1 UID: 0 PID: 6079 Comm: syz.3.33 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
RIP: 0010:__ns_ref_put include/linux/ns_common.h:255 [inline]
RIP: 0010:put_user_ns include/linux/user_namespace.h:189 [inline]
RIP: 0010:delayed_free_pidns+0x118/0x150 kernel/pid_namespace.c:145
Code: 85 ed 7e 2b e8 99 9f 03 00 48 83 c3 a8 48 8b 3d 5e be c7 17 48 89 de 5b 41 5c 41 5e 41 5f 5d e9 1e 1e 5f 00 e8 79 9f 03 00 90 <0f> 0b 90 eb b4 e8 6e 9f 03 00 4c 89 ff be 03 00 00 00 e8 01 fb d2
RSP: 0018:ffffc90000a08bb0 EFLAGS: 00010246
RAX: ffffffff81bde0b7 RBX: ffff88801e3a45b8 RCX: ffff888026cf5b80
RDX: 0000000000000100 RSI: 0000000000000002 RDI: 0000000000000000
RBP: 0000000000000002 R08: ffff888059ed4193 R09: 1ffff1100b3da832
R10: dffffc0000000000 R11: ffffed100b3da833 R12: dffffc0000000000
R13: ffffffff81a903d7 R14: ffff888059ed4000 R15: ffff888059ed4190
FS:  0000000000000000(0000) GS:ffff888125fc2000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f1d82e36504 CR3: 0000000023b54000 CR4: 00000000003526f0
Call Trace:
 <IRQ>
 rcu_do_batch kernel/rcu/tree.c:2605 [inline]
 rcu_core+0xcab/0x1770 kernel/rcu/tree.c:2861
 handle_softirqs+0x286/0x870 kernel/softirq.c:626
 __do_softirq kernel/softirq.c:660 [inline]
 invoke_softirq kernel/softirq.c:496 [inline]
 __irq_exit_rcu+0xca/0x1f0 kernel/softirq.c:727
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:743
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1052 [inline]
 sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1052
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0xa8/0x110 kernel/locking/spinlock.c:194
Code: 74 05 e8 6b 75 6a f6 48 c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f6 44 24 21 02 75 4f f7 c3 00 02 00 00 74 01 fb bf 01 00 00 00 <e8> c3 08 32 f6 65 8b 05 4c 10 17 07 85 c0 74 40 48 c7 04 24 0e 36
RSP: 0018:ffffc9000486f100 EFLAGS: 00000206
RAX: 0bb2b1353a7d7400 RBX: 0000000000000a06 RCX: 0bb2b1353a7d7400
RDX: 0000000000000000 RSI: ffffffff8d786e5e RDI: 0000000000000001
RBP: ffffc9000486f190 R08: ffffffff8f7da977 R09: 1ffffffff1efb52e
R10: dffffc0000000000 R11: fffffbfff1efb52f R12: dffffc0000000000
R13: ffffc9000486f458 R14: ffff88801ca91118 R15: 1ffff9200090de20
 spin_unlock_irqrestore include/linux/spinlock.h:406 [inline]
 unlock_page_lruvec_irqrestore include/linux/memcontrol.h:1509 [inline]
 folios_put_refs+0x51a/0x670 mm/swap.c:994
 folio_batch_release include/linux/pagevec.h:101 [inline]
 shmem_undo_range+0x49e/0x1490 mm/shmem.c:1149
 shmem_truncate_range mm/shmem.c:1261 [inline]
 shmem_evict_inode+0x272/0xa70 mm/shmem.c:1389
 evict+0x5f4/0xae0 fs/inode.c:837
 __dentry_kill+0x209/0x660 fs/dcache.c:669
 dput+0x19f/0x2b0 fs/dcache.c:911
 __fput+0x68e/0xa70 fs/file_table.c:476
 task_work_run+0x1d4/0x260 kernel/task_work.c:233
 exit_task_work include/linux/task_work.h:40 [inline]
 do_exit+0x6bd/0x2300 kernel/exit.c:970
 do_group_exit+0x21c/0x2d0 kernel/exit.c:1111
 get_signal+0x1285/0x1340 kernel/signal.c:3034
 arch_do_signal_or_restart+0x9a/0x7a0 arch/x86/kernel/signal.c:337
 __exit_to_user_mode_loop kernel/entry/common.c:41 [inline]
 exit_to_user_mode_loop+0x87/0x4f0 kernel/entry/common.c:75
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:159 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline]
 do_syscall_64+0x2e9/0xfa0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f248f78f6c9
Code: Unable to access opcode bytes at 0x7f248f78f69f.
RSP: 002b:00007f24905e6fe8 EFLAGS: 00000206 ORIG_RAX: 0000000000000038
RAX: fffffffffffffffc RBX: 00007f248f9e6270 RCX: 00007f248f78f6c9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00000000f5982400
RBP: 00007f248f811f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 00007f248f9e6308 R14: 00007f248f9e6270 R15: 00007ffd09e91998
 </TASK>
----------------
Code disassembly (best guess):
   0:	74 05                	je     0x7
   2:	e8 6b 75 6a f6       	call   0xf66a7572
   7:	48 c7 44 24 20 00 00 	movq   $0x0,0x20(%rsp)
   e:	00 00
  10:	9c                   	pushf
  11:	8f 44 24 20          	pop    0x20(%rsp)
  15:	f6 44 24 21 02       	testb  $0x2,0x21(%rsp)
  1a:	75 4f                	jne    0x6b
  1c:	f7 c3 00 02 00 00    	test   $0x200,%ebx
  22:	74 01                	je     0x25
  24:	fb                   	sti
  25:	bf 01 00 00 00       	mov    $0x1,%edi
* 2a:	e8 c3 08 32 f6       	call   0xf63208f2 <-- trapping instruction
  2f:	65 8b 05 4c 10 17 07 	mov    %gs:0x717104c(%rip),%eax        # 0x7171082
  36:	85 c0                	test   %eax,%eax
  38:	74 40                	je     0x7a
  3a:	48                   	rex.W
  3b:	c7                   	.byte 0xc7
  3c:	04 24                	add    $0x24,%al
  3e:	0e                   	(bad)
  3f:	36                   	ss