------------[ cut here ]------------
WARNING: CPU: 1 PID: 30732 at fs/namespace.c:1186 mntput_no_expire+0xade/0xcc0 fs/namespace.c:1186
Modules linked in:
CPU: 1 PID: 30732 Comm: syz-executor.0 Not tainted 5.12.0-next-20210504-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 2a 79 89 be c3 02 00 00 48 c7 c7 a0 2a 79 89 c6 05 7d 14 e7 0b 01 e8 c6 25 07 07 e9 3f fd ff ff e8 02 05 a7 ff <0f> 0b e9 fc fc ff ff e8 f6 04 a7 ff e8 91 ea 92 ff 31 ff 89 c5 89
RSP: 0018:ffffc90019667b80 EFLAGS: 00010246
RAX: 0000000000040000 RBX: 1ffff920032ccf76 RCX: ffffc90001c51000
RDX: 0000000000040000 RSI: ffffffff81cdcdfe RDI: 0000000000000003
RBP: ffff888072d53b00 R08: 0000000000000000 R09: ffffffff902268af
R10: ffffffff81cdcaf8 R11: 0000000000000000 R12: 0000000000000008
R13: ffffc90019667bd0 R14: 00000000fffffffb R15: 0000000000000002
FS:  00007f7279c24700(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2d833000 CR3: 0000000065c66000 CR4: 00000000001526e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 mntput fs/namespace.c:1232 [inline]
 cleanup_mnt+0x23d/0x540 fs/namespace.c:1132
 task_work_run+0xdd/0x1a0 kernel/task_work.c:164
 get_signal+0x1ba2/0x2150 kernel/signal.c:2591
 arch_do_signal_or_restart+0x2a8/0x1eb0 arch/x86/kernel/signal.c:789
 handle_signal_work kernel/entry/common.c:147 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:171 [inline]
 exit_to_user_mode_prepare+0x171/0x280 kernel/entry/common.c:208
 __syscall_exit_to_user_mode_work kernel/entry/common.c:290 [inline]
 syscall_exit_to_user_mode+0x19/0x60 kernel/entry/common.c:301
 do_syscall_64+0x47/0xb0 arch/x86/entry/common.c:57
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x4665f9
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:00007f7279c24188 EFLAGS: 00000246 ORIG_RAX: 0000000000000038
RAX: fffffffffffffffc RBX: 000000000056bf60 RCX: 00000000004665f9
RDX: 9999999999999999 RSI: 0000000000000000 RDI: 0c75e43cfae22dd4
RBP: 00000000004bfce1 R08: ffffffffffffffff R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf60
R13: 00007ffcb90ba8bf R14: 00007f7279c24300 R15: 0000000000022000