------------[ cut here ]------------
WARNING: CPU: 1 PID: 24937 at fs/namespace.c:1186 mntput_no_expire+0xaca/0xcb0 fs/namespace.c:1186
Modules linked in:
CPU: 1 PID: 24937 Comm: syz-executor.4 Not tainted 5.12.0-rc7-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 75 70 e5 0b 01 e8 7a 3f f7 06 e9 3f fd ff ff e8 a6 93 a8 ff <0f> 0b e9 fc fc ff ff e8 9a 93 a8 ff e8 35 ca 94 ff 31 ff 89 c5 89
RSP: 0018:ffffc9000171fbe0 EFLAGS: 00010293
RAX: 0000000000000000 RBX: 1ffff920002e3f82 RCX: 0000000000000000
RDX: ffff88801fc90000 RSI: ffffffff81cb5dda RDI: 0000000000000003
RBP: ffff88805e2e8300 R08: 0000000000000000 R09: ffffffff8fa9a8af
R10: ffffffff81cb5ad4 R11: 0000000000000000 R12: 0000000000000008
R13: ffffc9000171fc30 R14: dffffc0000000000 R15: 00000000ffffffff
FS:  0000000000000000(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000002996848 CR3: 000000005bd0c000 CR4: 00000000001506e0
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: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
 do_exit+0xbf7/0x2a60 kernel/exit.c:824
 do_group_exit+0x125/0x310 kernel/exit.c:922
 __do_sys_exit_group kernel/exit.c:933 [inline]
 __se_sys_exit_group kernel/exit.c:931 [inline]
 __x64_sys_exit_group+0x3a/0x50 kernel/exit.c:931
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x4665f9
Code: Unable to access opcode bytes at RIP 0x4665cf.
RSP: 002b:00007fff7b2fed58 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 00007fff7b2fef10 RCX: 00000000004665f9
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000043
RBP: 0000000000000000 R08: 0000000000000025 R09: 00007fff7b2fef10
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000004bfcb2
R13: 000000000000001c R14: 00000000ffffffff R15: 00007fff7b2fef50