------------[ cut here ]------------
WARNING: ./include/linux/ns_common.h:255 at __ns_ref_put include/linux/ns_common.h:255 [inline], CPU#1: kworker/u8:7/5965
WARNING: ./include/linux/ns_common.h:255 at put_user_ns include/linux/user_namespace.h:189 [inline], CPU#1: kworker/u8:7/5965
WARNING: ./include/linux/ns_common.h:255 at put_cred_rcu+0x2c5/0x340 kernel/cred.c:61, CPU#1: kworker/u8:7/5965
Modules linked in:
CPU: 1 UID: 0 PID: 5965 Comm: kworker/u8:7 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: events_unbound nsim_dev_trap_report_work
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:put_cred_rcu+0x2c5/0x340 kernel/cred.c:61
Code: 5c 41 5d 41 5e 41 5f 5d e9 d8 e3 8d 00 e8 23 8e 32 00 4c 89 e7 be 03 00 00 00 e8 76 5a 00 03 e9 b8 fe ff ff e8 0c 8e 32 00 90 <0f> 0b 90 eb 9f e8 01 8e 32 00 4c 89 ff be 03 00 00 00 e8 54 5a 00
RSP: 0018:ffffc90000a08ba8 EFLAGS: 00010246
RAX: ffffffff818e9174 RBX: ffff888026b42aa0 RCX: ffff8880345bdb80
RDX: 0000000000000100 RSI: 0000000000000004 RDI: 0000000000000000
RBP: 0000000000000004 R08: ffff88805a66c193 R09: 1ffff1100b4cd832
R10: dffffc0000000000 R11: ffffed100b4cd833 R12: dffffc0000000000
R13: ffff888026b42a00 R14: ffff88805a66c000 R15: ffff88805a66c190
FS:  0000000000000000(0000) GS:ffff888125fcc000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fcb1735bf98 CR3: 000000000dd38000 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+0x27d/0x880 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:1055 [inline]
 sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1055
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:unwind_next_frame+0x374/0x2390 arch/x86/kernel/unwind_orc.c:505
Code: ea 48 01 d2 48 01 f2 48 bd 00 00 00 00 00 fc ff df 0f 84 37 01 00 00 4c 8d 62 04 4c 8d 6a 05 4c 89 e0 48 c1 e8 03 0f b6 04 28 <84> c0 0f 85 6d 19 00 00 4c 89 e8 48 c1 e8 03 0f b6 04 28 84 c0 0f
RSP: 0018:ffffc90004867458 EFLAGS: 00000a07
RAX: 0000000000000000 RBX: ffffffff8f925a78 RCX: ffffffff8f925a7c
RDX: ffffffff900dc0c2 RSI: ffffffff900dc0c2 RDI: ffffffff8bbf4100
RBP: dffffc0000000000 R08: 0000000000000001 R09: ffffffff8173cfd5
R10: ffffc90004867578 R11: ffffffff81ad25e0 R12: ffffffff900dc0c6
R13: ffffffff900dc0c7 R14: ffffc90004867528 R15: ffffffff8f925a78
 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
 kasan_save_stack mm/kasan/common.c:56 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:77
 unpoison_slab_object mm/kasan/common.c:339 [inline]
 __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:365
 kasan_slab_alloc include/linux/kasan.h:252 [inline]
 slab_post_alloc_hook mm/slub.c:4950 [inline]
 slab_alloc_node mm/slub.c:5260 [inline]
 kmem_cache_alloc_node_noprof+0x43c/0x710 mm/slub.c:5312
 __alloc_skb+0x112/0x2d0 net/core/skbuff.c:663
 alloc_skb include/linux/skbuff.h:1383 [inline]
 nsim_dev_trap_skb_build drivers/net/netdevsim/dev.c:763 [inline]
 nsim_dev_trap_report drivers/net/netdevsim/dev.c:820 [inline]
 nsim_dev_trap_report_work+0x29a/0xb80 drivers/net/netdevsim/dev.c:866
 process_one_work+0x93a/0x15e0 kernel/workqueue.c:3261
 process_scheduled_works kernel/workqueue.c:3344 [inline]
 worker_thread+0x9b0/0xee0 kernel/workqueue.c:3425
 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:245
 </TASK>
----------------
Code disassembly (best guess), 1 bytes skipped:
   0:	48 01 d2             	add    %rdx,%rdx
   3:	48 01 f2             	add    %rsi,%rdx
   6:	48 bd 00 00 00 00 00 	movabs $0xdffffc0000000000,%rbp
   d:	fc ff df
  10:	0f 84 37 01 00 00    	je     0x14d
  16:	4c 8d 62 04          	lea    0x4(%rdx),%r12
  1a:	4c 8d 6a 05          	lea    0x5(%rdx),%r13
  1e:	4c 89 e0             	mov    %r12,%rax
  21:	48 c1 e8 03          	shr    $0x3,%rax
  25:	0f b6 04 28          	movzbl (%rax,%rbp,1),%eax
* 29:	84 c0                	test   %al,%al <-- trapping instruction
  2b:	0f 85 6d 19 00 00    	jne    0x199e
  31:	4c 89 e8             	mov    %r13,%rax
  34:	48 c1 e8 03          	shr    $0x3,%rax
  38:	0f b6 04 28          	movzbl (%rax,%rbp,1),%eax
  3c:	84 c0                	test   %al,%al
  3e:	0f                   	.byte 0xf