------------[ cut here ]------------
dst_release underflow
WARNING: CPU: 1 PID: 11151 at net/core/dst.c:173 dst_release net/core/dst.c:173 [inline]
WARNING: CPU: 1 PID: 11151 at net/core/dst.c:173 dst_release+0xd2/0xe0 net/core/dst.c:167
Modules linked in:
CPU: 1 PID: 11151 Comm: syz-executor.2 Not tainted 5.16.0-rc2-next-20211125-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:dst_release net/core/dst.c:173 [inline]
RIP: 0010:dst_release+0xd2/0xe0 net/core/dst.c:167
Code: 89 c3 89 c6 e8 6f fc 41 fa 85 db 74 a4 e9 24 a9 13 02 e8 41 fa 41 fa 48 c7 c7 00 9e ad 8a c6 05 40 d3 46 06 01 e8 f4 e5 d4 01 <0f> 0b eb c6 66 2e 0f 1f 84 00 00 00 00 00 41 56 41 55 41 54 55 48
RSP: 0018:ffffc90003f6fbd0 EFLAGS: 00010282

RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000040000 RSI: ffffffff815f3208 RDI: fffff520007edf6c
RBP: ffffe8ffffc731a0 R08: 0000000000000000 R09: 0000000000000000
R10: ffffffff815ecfae R11: 0000000000000000 R12: ffffffff9084fb40
R13: 00000000ffffffff R14: 0000000000000007 R15: 0000000000000000
FS:  00007fde9a238700(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffe3810cfd0 CR3: 0000000084b7d000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 dst_cache_destroy net/core/dst_cache.c:160 [inline]
 dst_cache_destroy+0xcb/0x190 net/core/dst_cache.c:152
 ipip6_dev_free net/ipv6/sit.c:1414 [inline]
 sit_init_net+0x7d8/0xaa0 net/ipv6/sit.c:1936
 ops_init+0xaf/0x470 net/core/net_namespace.c:140
 setup_net+0x40f/0xa30 net/core/net_namespace.c:326
 copy_net_ns+0x318/0x760 net/core/net_namespace.c:470
 create_new_namespaces+0x3f6/0xb20 kernel/nsproxy.c:110
 unshare_nsproxy_namespaces+0xc1/0x1f0 kernel/nsproxy.c:226
 ksys_unshare+0x445/0x920 kernel/fork.c:3077
 __do_sys_unshare kernel/fork.c:3148 [inline]
 __se_sys_unshare kernel/fork.c:3146 [inline]
 __x64_sys_unshare+0x2d/0x40 kernel/fork.c:3146
 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: 0033:0x7fde9ccc2ae9
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:00007fde9a238188 EFLAGS: 00000246 ORIG_RAX: 0000000000000110
RAX: ffffffffffffffda RBX: 00007fde9cdd5f60 RCX: 00007fde9ccc2ae9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000040000000
RBP: 00007fde9cd1cf6d R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffc04c30c3f R14: 00007fde9a238300 R15: 0000000000022000
 </TASK>