------------[ cut here ]------------
ida_free called for id=1490 which is not allocated.
WARNING: CPU: 1 PID: 3518 at lib/idr.c:592 ida_free+0x280/0x310 lib/idr.c:592
Modules linked in:
CPU: 1 UID: 0 PID: 3518 Comm: kworker/u8:9 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Workqueue: netns cleanup_net
RIP: 0010:ida_free+0x280/0x310 lib/idr.c:592
Code: 00 00 00 00 fc ff df 48 8b 5c 24 10 48 8b 7c 24 40 48 89 de e8 31 28 0c 00 90 48 c7 c7 c0 26 76 8c 44 89 fe e8 e1 8c 55 f6 90 <0f> 0b 90 90 eb 34 e8 35 02 92 f6 49 bd 00 00 00 00 00 fc ff df eb
RSP: 0018:ffffc9000c10f6e0 EFLAGS: 00010246
RAX: 40391bdf9225d400 RBX: 0000000000000212 RCX: ffff8880303c8000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000002
RBP: ffffc9000c10f7d8 R08: ffff8880b8924293 R09: 1ffff11017124852
R10: dffffc0000000000 R11: ffffed1017124853 R12: 1ffff92001821ee0
R13: dffffc0000000000 R14: ffff88807cee2600 R15: 00000000000005d2
FS:  0000000000000000(0000) GS:ffff88812647e000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f79dedb6c60 CR3: 0000000037fe6000 CR4: 0000000000350ef0
Call Trace:
 <TASK>
 proc_free_inum fs/proc/generic.c:216 [inline]
 pde_put+0x7e/0x1b0 fs/proc/generic.c:696
 remove_proc_subtree+0x370/0x530 fs/proc/generic.c:791
 remove_cache_proc_entries net/sunrpc/cache.c:1673 [inline]
 cache_unregister_net+0x52/0x90 net/sunrpc/cache.c:1733
 nfsd_export_shutdown+0x96/0x110 fs/nfsd/export.c:1509
 ops_exit_list net/core/net_namespace.c:199 [inline]
 ops_undo_list+0x49a/0x990 net/core/net_namespace.c:252
 cleanup_net+0x4d8/0x820 net/core/net_namespace.c:695
 process_one_work kernel/workqueue.c:3236 [inline]
 process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3319
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3400
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x439/0x7d0 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>