syzbot

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refcount_t: addition on 0; use-after-free.
WARNING: CPU: 1 PID: 8676 at lib/refcount.c:25 refcount_warn_saturate+0x169/0x1e0 lib/refcount.c:25
Modules linked in:
CPU: 0 PID: 8676 Comm: syz-executor.0 Not tainted 5.12.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:refcount_warn_saturate+0x169/0x1e0 lib/refcount.c:25
Code: 09 31 ff 89 de e8 77 36 ab fd 84 db 0f 85 36 ff ff ff e8 ba 2f ab fd 48 c7 c7 60 d8 c1 89 c6 05 c4 27 e8 09 01 e8 c3 86 f9 04 <0f> 0b e9 17 ff ff ff e8 9b 2f ab fd 0f b6 1d a9 27 e8 09 31 ff 89
RSP: 0018:ffffc90001fffd40 EFLAGS: 00010282
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: ffff88801b3e1c40 RSI: ffffffff815c4d15 RDI: fffff520003fff9a
RBP: 0000000000000002 R08: 0000000000000000 R09: 0000000000000000
R10: ffffffff815bdaae R11: 0000000000000000 R12: ffff88801d2d1000
R13: ffff88801884814c R14: 0000000000000010 R15: ffffffff8d66b640
FS:  00007fae2ad6d700(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f1903a02000 CR3: 0000000018aa1000 CR4: 00000000001506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 __refcount_add include/linux/refcount.h:199 [inline]
 __refcount_inc include/linux/refcount.h:250 [inline]
 refcount_inc include/linux/refcount.h:267 [inline]
 get_net include/net/net_namespace.h:240 [inline]
 sk_alloc+0xb20/0xbd0 net/core/sock.c:1768
 __netlink_create+0x63/0x2f0 net/netlink/af_netlink.c:638
 netlink_create+0x3a1/0x5d0 net/netlink/af_netlink.c:701
 __sock_create+0x3de/0x780 net/socket.c:1408
 sock_create net/socket.c:1459 [inline]
 __sys_socket+0xef/0x200 net/socket.c:1501
 __do_sys_socket net/socket.c:1510 [inline]
 __se_sys_socket net/socket.c:1508 [inline]
 __x64_sys_socket+0x6f/0xb0 net/socket.c:1508
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x466459
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:00007fae2ad6d188 EFLAGS: 00000246
 ORIG_RAX: 0000000000000029
RAX: ffffffffffffffda RBX: 000000000056bf60 RCX: 0000000000466459
RDX: 0000000000000000 RSI: 0000000000000003 RDI: 0000000000000010
RBP: 00000000004bf9fb R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf60
R13: 00007fff7252ed2f R14: 00007fae2ad6d300 R15: 0000000000022000