------------[ cut here ]------------
ida_free called for id=1051 which is not allocated.
WARNING: CPU: 1 PID: 6111 at lib/idr.c:592 ida_free+0x1f9/0x2e0 lib/idr.c:592
Modules linked in:
CPU: 1 UID: 0 PID: 6111 Comm: syz.1.25 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
RIP: 0010:ida_free+0x1f9/0x2e0 lib/idr.c:592
Code: 33 f6 41 83 fe 3e 76 72 e8 14 31 33 f6 48 8b 7c 24 28 4c 89 ee e8 57 65 0d 00 90 48 c7 c7 e0 17 16 8d 89 ee e8 78 13 f2 f5 90 <0f> 0b 90 90 e8 ee 30 33 f6 48 b8 00 00 00 00 00 fc ff df 48 01 c3
RSP: 0018:ffffc9000353fc00 EFLAGS: 00010282
RAX: 0000000000000000 RBX: 1ffff920006a7f81 RCX: ffffffff817a02f8
RDX: ffff88802fdb3c00 RSI: ffffffff817a0305 RDI: 0000000000000001
RBP: 000000000000041b R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000001 R12: ffff88802fa94300
R13: 0000000000000293 R14: 000000000000001b R15: ffff88802fa94300
FS:  00007fb5b7ffe6c0(0000) GS:ffff8881247b3000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f32eb3b4f98 CR3: 000000007eaa2000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 free_mnt_ns+0xe0/0x110 fs/namespace.c:4096
 namespace_unlock+0x542/0x920 fs/namespace.c:1701
 put_mnt_ns fs/namespace.c:6135 [inline]
 put_mnt_ns+0xf5/0x120 fs/namespace.c:6126
 free_nsproxy+0x3a/0x400 kernel/nsproxy.c:188
 put_nsproxy include/linux/nsproxy.h:107 [inline]
 switch_task_namespaces+0xeb/0x100 kernel/nsproxy.c:241
 ksys_unshare+0x521/0xa40 kernel/fork.c:3152
 __do_sys_unshare kernel/fork.c:3198 [inline]
 __se_sys_unshare kernel/fork.c:3196 [inline]
 __x64_sys_unshare+0x31/0x40 kernel/fork.c:3196
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fb5b898eec9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fb5b7ffe038 EFLAGS: 00000246 ORIG_RAX: 0000000000000110
RAX: ffffffffffffffda RBX: 00007fb5b8be5fa0 RCX: 00007fb5b898eec9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000020000
RBP: 00007fb5b8a11f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fb5b8be6038 R14: 00007fb5b8be5fa0 R15: 00007ffee29bc268
 </TASK>