------------[ cut here ]------------
ida_free called for id=964 which is not allocated.
WARNING: CPU: 0 PID: 9471 at lib/idr.c:592 ida_free+0x280/0x310
Modules linked in:
CPU: 0 UID: 0 PID: 9471 Comm: syz.8.813 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
RIP: 0010:ida_free+0x280/0x310
Code: 00 00 00 00 fc ff df 48 8b 5c 24 10 48 8b 7c 24 40 48 89 de e8 71 2c 0c 00 90 48 c7 c7 a0 7b 76 8c 44 89 fe e8 41 11 54 f6 90 <0f> 0b 90 90 eb 34 e8 85 a2 90 f6 49 bd 00 00 00 00 00 fc ff df eb
RSP: 0018:ffffc900079a7880 EFLAGS: 00010246
RAX: 0ce2420139690c00 RBX: 0000000000000a06 RCX: ffff88810852ba00
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000002
RBP: ffffc900079a7968 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffffbfff1b7a138 R12: 1ffff92000f34f14
R13: dffffc0000000000 R14: ffff88801ce8a000 R15: 00000000000003c4
FS:  00007f5635b576c0(0000) GS:ffff8880b8d73000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055fe04a5b000 CR3: 000000010fba2000 CR4: 00000000000006f0
DR0: 0000200000000300 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <TASK>
 free_mnt_ns+0x52/0xe0
 namespace_unlock+0x529/0x760
 free_nsproxy+0x3e/0x350
 do_exit+0x6b0/0x2300
 do_group_exit+0x21c/0x2d0
 get_signal+0x1285/0x1340
 arch_do_signal_or_restart+0xa0/0x790
 exit_to_user_mode_loop+0x72/0x110
 do_syscall_64+0x2bd/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f5634d8ec29
Code: Unable to access opcode bytes at 0x7f5634d8ebff.
RSP: 002b:00007f5635b570e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 00007f5634fd5fa8 RCX: 00007f5634d8ec29
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f5634fd5fa8
RBP: 00007f5634fd5fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f5634fd6038 R14: 00007ffce674ab90 R15: 00007ffce674ac78
 </TASK>
