------------[ cut here ]------------
WARNING: ./include/linux/ns_common.h:255 at __ns_ref_put include/linux/ns_common.h:255 [inline], CPU#0: syz-executor/5829
WARNING: ./include/linux/ns_common.h:255 at put_user_ns include/linux/user_namespace.h:189 [inline], CPU#0: syz-executor/5829
WARNING: ./include/linux/ns_common.h:255 at put_cred_rcu+0x2c5/0x340 kernel/cred.c:61, CPU#0: syz-executor/5829
Modules linked in:
CPU: 0 UID: 0 PID: 5829 Comm: syz-executor 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: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:ffffc90000007c48 EFLAGS: 00010246
RAX: ffffffff818e9174 RBX: ffff88802d9e34a0 RCX: ffff88807bb25b80
RDX: 0000000000000100 RSI: 0000000000000002 RDI: 0000000000000000
RBP: 0000000000000002 R08: ffff88805891c193 R09: 1ffff1100b123832
R10: dffffc0000000000 R11: ffffed100b123833 R12: dffffc0000000000
R13: ffff88802d9e3400 R14: ffff88805891c000 R15: ffff88805891c190
FS:  000055556a83f500(0000) GS:ffff888125ecc000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffeadeb1ec0 CR3: 0000000061bee000 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+0xec/0x180 kernel/softirq.c:523
 </IRQ>
 <TASK>
 __local_bh_enable_ip+0x17d/0x1c0 kernel/softirq.c:450
 local_bh_enable include/linux/bottom_half.h:33 [inline]
 fpregs_unlock arch/x86/include/asm/fpu/api.h:77 [inline]
 copy_fpstate_to_sigframe+0x547/0xce0 arch/x86/kernel/fpu/signal.c:220
 get_sigframe+0x58d/0x7d0 arch/x86/kernel/signal.c:163
 x64_setup_rt_frame+0x15b/0xd40 arch/x86/kernel/signal_64.c:175
 setup_rt_frame arch/x86/kernel/signal.c:250 [inline]
 handle_signal arch/x86/kernel/signal.c:294 [inline]
 arch_do_signal_or_restart+0x3d1/0x7a0 arch/x86/kernel/signal.c:339
 __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: 0033:0x7fa1da5c1f85
Code: 24 0c 89 3c 24 48 89 4c 24 18 e8 f6 54 ff ff 4c 8b 54 24 18 48 8b 54 24 10 41 89 c0 8b 74 24 0c 8b 3c 24 b8 e6 00 00 00 0f 05 <44> 89 c7 48 89 04 24 e8 4f 55 ff ff 48 8b 04 24 48 83 c4 28 f7 d8
RSP: 002b:00007ffeadeb2290 EFLAGS: 00000293 ORIG_RAX: 00000000000000e6
RAX: fffffffffffffffc RBX: 0000000000000060 RCX: 00007fa1da5c1f85
RDX: 00007ffeadeb22d0 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007ffeadeb233c R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000001388
R13: 00000000000927c0 R14: 000000000001adbf R15: 00007ffeadeb2390
 </TASK>