------------[ cut here ]------------
WARNING: CPU: 0 PID: 2574 at fs/namespace.c:1187 mntput_no_expire+0xada/0xcd0 fs/namespace.c:1187
Modules linked in:
CPU: 0 PID: 2574 Comm: kworker/0:30 Not tainted 5.14.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events free_ipc
RIP: 0010:mntput_no_expire+0xada/0xcd0 fs/namespace.c:1187
Code: 30 84 c0 0f 84 b9 fe ff ff 3c 03 0f 8f b1 fe ff ff 4c 89 44 24 10 e8 c5 f7 eb ff 4c 8b 44 24 10 e9 9d fe ff ff e8 86 b6 a4 ff <0f> 0b e9 19 fd ff ff e8 7a b6 a4 ff e8 e5 46 63 07 31 ff 89 c5 89
RSP: 0018:ffffc90001d2fc08 EFLAGS: 00010293
RAX: 0000000000000000 RBX: 1ffff920003a5f87 RCX: 0000000000000000
RDX: ffff888078550000 RSI: ffffffff81d15ada RDI: 0000000000000003
RBP: ffff8880515ab980 R08: 0000000000000000 R09: ffffffff8fcfd8ef
R10: ffffffff81d157f1 R11: 0000000000000000 R12: 0000000000000008
R13: ffffc90001d2fc58 R14: 00000000ffffffff R15: 0000000000000002
FS:  0000000000000000(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055cdc0944458 CR3: 000000002f37d000 CR4: 00000000001506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 mntput fs/namespace.c:1233 [inline]
 kern_unmount fs/namespace.c:4369 [inline]
 kern_unmount+0xb5/0xe0 fs/namespace.c:4363
 free_ipc_ns ipc/namespace.c:123 [inline]
 free_ipc+0xf0/0x200 ipc/namespace.c:141
 process_one_work+0x9bf/0x16b0 kernel/workqueue.c:2297
 worker_thread+0x658/0x11f0 kernel/workqueue.c:2444
 kthread+0x3e5/0x4d0 kernel/kthread.c:319
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295