------------[ cut here ]------------
WARNING: CPU: 0 PID: 32022 at fs/namespace.c:1186 mntput_no_expire+0xade/0xcc0 fs/namespace.c:1186
Modules linked in:
CPU: 0 PID: 32022 Comm: syz-executor.5 Tainted: G        W         5.13.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:mntput_no_expire+0xade/0xcc0 fs/namespace.c:1186
Code: ff 48 c7 c2 e0 5b 99 89 be d1 02 00 00 48 c7 c7 a0 5b 99 89 c6 05 35 58 07 0c 01 e8 98 91 10 07 e9 3f fd ff ff e8 42 24 a6 ff <0f> 0b e9 fc fc ff ff e8 36 24 a6 ff e8 11 fc 91 ff 31 ff 89 c5 89
RSP: 0018:ffffc9000335fc18 EFLAGS: 00010293
RAX: 0000000000000000 RBX: 1ffff9200066bf89 RCX: 0000000000000000
RDX: ffff88804a708000 RSI: ffffffff81cf65ee RDI: 0000000000000003
RBP: ffff88803a615200 R08: 0000000000000000 R09: ffffffff8deb5217
R10: ffffffff81cf62e8 R11: 0000000000000000 R12: 0000000000000008
R13: ffffc9000335fc68 R14: 00000000fffffff9 R15: 0000000000000002
FS:  00007f09091aa700(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000000252d708 CR3: 000000002165d000 CR4: 00000000001506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 mntput fs/namespace.c:1232 [inline]
 namespace_unlock+0x26b/0x410 fs/namespace.c:1451
 drop_collected_mounts fs/namespace.c:1938 [inline]
 put_mnt_ns fs/namespace.c:4259 [inline]
 put_mnt_ns+0x106/0x140 fs/namespace.c:4255
 create_new_namespaces+0x6d1/0xb20 kernel/nsproxy.c:141
 unshare_nsproxy_namespaces+0xbd/0x1f0 kernel/nsproxy.c:226
 ksys_unshare+0x445/0x920 kernel/fork.c:3002
 __do_sys_unshare kernel/fork.c:3076 [inline]
 __se_sys_unshare kernel/fork.c:3074 [inline]
 __x64_sys_unshare+0x2d/0x40 kernel/fork.c:3074
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x4665d9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f09091aa188 EFLAGS: 00000246 ORIG_RAX: 0000000000000110
RAX: ffffffffffffffda RBX: 000000000056c038 RCX: 00000000004665d9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 000000006c060000
RBP: 00000000004bfcb9 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056c038
R13: 0000000000a9fb1f R14: 00007f09091aa300 R15: 0000000000022000