------------[ cut here ]------------
WARNING: CPU: 1 PID: 17508 at fs/namespace.c:1186 mntput_no_expire+0xaca/0xcb0 fs/namespace.c:1186
Modules linked in:
CPU: 1 PID: 17508 Comm: syz-executor.5 Not tainted 5.12.0-rc8-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:mntput_no_expire+0xaca/0xcb0 fs/namespace.c:1186
Code: ff 48 c7 c2 a0 cd 78 89 be c2 02 00 00 48 c7 c7 60 cd 78 89 c6 05 35 6a e5 0b 01 e8 3a 4b f7 06 e9 3f fd ff ff e8 36 93 a8 ff <0f> 0b e9 fc fc ff ff e8 2a 93 a8 ff e8 f5 c5 94 ff 31 ff 89 c5 89
RSP: 0018:ffffc90007167c70 EFLAGS: 00010212
RAX: 0000000000000b5f RBX: 1ffff92000e2cf94 RCX: ffffc90013a6c000
RDX: 0000000000040000 RSI: ffffffff81cb621a RDI: 0000000000000003
RBP: ffff88801a6bed80 R08: 0000000000000000 R09: ffffffff8fa9a8af
R10: ffffffff81cb5f14 R11: 0000000000000000 R12: 0000000000000008
R13: ffffc90007167cc0 R14: dffffc0000000000 R15: 00000000fffffffc
FS:  00007fb8731a9700(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b33b2c000 CR3: 000000002ca8b000 CR4: 00000000001506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 00000000b8fecd19 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 mntput fs/namespace.c:1232 [inline]
 namespace_unlock+0x26b/0x410 fs/namespace.c:1450
 drop_collected_mounts fs/namespace.c:1937 [inline]
 put_mnt_ns fs/namespace.c:4250 [inline]
 put_mnt_ns+0x106/0x140 fs/namespace.c:4246
 free_nsproxy+0x43/0x4c0 kernel/nsproxy.c:191
 put_nsproxy include/linux/nsproxy.h:105 [inline]
 switch_task_namespaces+0xaf/0xd0 kernel/nsproxy.c:249
 commit_nsset kernel/nsproxy.c:523 [inline]
 __do_sys_setns+0xd47/0x1720 kernel/nsproxy.c:560
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 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:00007fb8731a9188 EFLAGS: 00000246 ORIG_RAX: 0000000000000134
RAX: ffffffffffffffda RBX: 000000000056bf60 RCX: 00000000004665f9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000004
RBP: 00000000004bfbb9 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf60
R13: 0000000000a9fb1f R14: 00007fb8731a9300 R15: 0000000000022000