------------[ cut here ]------------ ida_free called for id=1001 which is not allocated. WARNING: CPU: 0 PID: 8204 at lib/idr.c:592 ida_free+0x1f9/0x2e0 lib/idr.c:592 Modules linked in: CPU: 0 UID: 0 PID: 8204 Comm: kworker/u10:15 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+0x1f9/0x2e0 lib/idr.c:592 Code: 7c f6 41 83 fe 3e 76 72 e8 d4 44 7c f6 48 8b 7c 24 28 4c 89 ee e8 77 01 0d 00 90 48 c7 c7 c0 73 cf 8c 89 ee e8 a8 1a 3b f6 90 <0f> 0b 90 90 e8 ae 44 7c f6 48 b8 00 00 00 00 00 fc ff df 48 01 c3 RSP: 0000:ffffc90002f37ad0 EFLAGS: 00010282 RAX: 0000000000000000 RBX: 1ffff920005e6f5b RCX: ffffffff81797ce8 RDX: ffff888027fb0000 RSI: ffffffff81797cf5 RDI: 0000000000000001 RBP: 00000000000003e9 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000011698 R12: ffff88801e6b0000 R13: 0000000000000293 R14: 00000000000003e9 R15: ffff88801e6b0078 FS: 0000000000000000(0000) GS:ffff888124e8c000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b33405ff8 CR3: 00000000646e2000 CR4: 00000000003526f0 Call Trace: cleanup_net+0x5ad/0x8b0 net/core/net_namespace.c:709 process_one_work+0x9cc/0x1b70 kernel/workqueue.c:3263 process_scheduled_works kernel/workqueue.c:3346 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3427 kthread+0x3c5/0x780 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