------------[ cut here ]------------
ida_free called for id=949 which is not allocated.
WARNING: CPU: 1 PID: 8353 at lib/idr.c:592 ida_free+0x1f9/0x2e0 lib/idr.c:592
Modules linked in:
CPU: 1 UID: 0 PID: 8353 Comm: kworker/u8:36 Tainted: G     U              syzkaller #0 PREEMPT(full) 
Tainted: [U]=USER
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Workqueue: netns cleanup_net
RIP: 0010:ida_free+0x1f9/0x2e0 lib/idr.c:592
Code: 76 f6 41 83 fe 3e 76 72 e8 24 78 76 f6 48 8b 7c 24 28 4c 89 ee e8 07 39 0d 00 90 48 c7 c7 00 ba cf 8c 89 ee e8 e8 52 35 f6 90 <0f> 0b 90 90 e8 fe 77 76 f6 48 b8 00 00 00 00 00 fc ff df 48 01 c3
RSP: 0018:ffffc9000e0bf570 EFLAGS: 00010282
RAX: 0000000000000000 RBX: 1ffff92001c17eaf RCX: ffffffff81796528
RDX: ffff88802e54dac0 RSI: ffffffff81796535 RDI: 0000000000000001
RBP: 00000000000003b5 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: ffff88801e6d7000
R13: 0000000000000293 R14: 00000000000003b5 R15: ffff88801e6d7070
FS:  0000000000000000(0000) GS:ffff888124f5d000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000007d374000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 proc_free_inum fs/proc/generic.c:216 [inline]
 pde_put fs/proc/generic.c:696 [inline]
 pde_put+0xa9/0x1d0 fs/proc/generic.c:693
 remove_proc_subtree+0x487/0x5e0 fs/proc/generic.c:796
 proc_remove fs/proc/generic.c:811 [inline]
 proc_remove+0x6a/0x90 fs/proc/generic.c:808
 snmp6_unregister_dev+0xc4/0x140 net/ipv6/proc.c:274
 addrconf_ifdown.isra.0+0x44d/0x1aa0 net/ipv6/addrconf.c:3870
 addrconf_notify+0x220/0x19e0 net/ipv6/addrconf.c:3776
 notifier_call_chain+0xbc/0x410 kernel/notifier.c:85
 call_netdevice_notifiers_info+0xbe/0x140 net/core/dev.c:2229
 call_netdevice_notifiers_extack net/core/dev.c:2267 [inline]
 call_netdevice_notifiers net/core/dev.c:2281 [inline]
 unregister_netdevice_many_notify+0xf76/0x24c0 net/core/dev.c:12166
 ops_exit_rtnl_list net/core/net_namespace.c:187 [inline]
 ops_undo_list+0x8fc/0xab0 net/core/net_namespace.c:248
 cleanup_net+0x41b/0x8b0 net/core/net_namespace.c:695
 process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3263
 process_scheduled_works kernel/workqueue.c:3346 [inline]
 worker_thread+0x6c8/0xf10 kernel/workqueue.c:3427
 kthread+0x3c2/0x780 kernel/kthread.c:463
 ret_from_fork+0x56d/0x730 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>