------------[ cut here ]------------
dst_release underflow
WARNING: CPU: 0 PID: 10420 at net/core/dst.c:175 dst_release net/core/dst.c:175 [inline]
WARNING: CPU: 0 PID: 10420 at net/core/dst.c:175 dst_release+0xd2/0xe0 net/core/dst.c:169
Modules linked in:
CPU: 0 PID: 10420 Comm: syz-executor.4 Not tainted 5.13.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:dst_release net/core/dst.c:175 [inline]
RIP: 0010:dst_release+0xd2/0xe0 net/core/dst.c:169
Code: 89 c3 89 c6 e8 ef 92 60 fa 85 db 74 a4 e9 95 a1 07 02 e8 a1 8b 60 fa 48 c7 c7 80 3b 8a 8a c6 05 17 e7 c1 06 01 e8 1b a3 ca 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:ffffc9000b9c7bb0 EFLAGS: 00010286
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000040000 RSI: ffffffff815d7275 RDI: fffff52001738f68
RBP: ffffe8ffffcc9668 R08: 0000000000000000 R09: 0000000000000000
R10: ffffffff815d10de R11: 0000000000000000 R12: ffffe8ffffcc9668
R13: 00000000ffffffff R14: 0000000000000007 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8880b9c00000(0063) knlGS:00000000f5580b40
CS:  0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: 0000000020000000 CR3: 000000002f3f4000 CR4: 00000000001506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 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:1412 [inline]
 sit_init_net+0x88b/0xa80 net/ipv6/sit.c:1934
 ops_init+0xaf/0x470 net/core/net_namespace.c:140
 setup_net+0x40f/0xa30 net/core/net_namespace.c:333
 copy_net_ns+0x31e/0x760 net/core/net_namespace.c:474
 create_new_namespaces+0x3f6/0xb20 kernel/nsproxy.c:110
 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]
 __ia32_sys_unshare+0x2c/0x40 kernel/fork.c:3074
 do_syscall_32_irqs_on arch/x86/entry/common.c:112 [inline]
 __do_fast_syscall_32+0x65/0xf0 arch/x86/entry/common.c:178
 do_fast_syscall_32+0x2f/0x70 arch/x86/entry/common.c:203
 entry_SYSENTER_compat_after_hwframe+0x4d/0x5c
RIP: 0023:0xf7f86549
Code: 03 74 c0 01 10 05 03 74 b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00
RSP: 002b:00000000f55805fc EFLAGS: 00000296 ORIG_RAX: 0000000000000136
RAX: ffffffffffffffda RBX: 0000000060000000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000