------------[ cut here ]------------
refcount_t: underflow; use-after-free.
WARNING: CPU: 0 PID: 5900 at lib/refcount.c:28 refcount_warn_saturate+0x12b/0x140 lib/refcount.c:28
Modules linked in:
CPU: 1 PID: 5900 Comm: syz-executor575 Not tainted 5.12.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:refcount_warn_saturate+0x12b/0x140 lib/refcount.c:28
Code: e5 87 04 0f 0b e9 53 ff ff ff 48 89 df e8 1d dc 29 fe e9 23 ff ff ff 48 c7 c7 c0 8e fd 88 c6 05 88 0f ca 08 01 e8 bc e5 87 04 <0f> 0b e9 2c ff ff ff 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 41
RSP: 0018:ffffc90001867af8 EFLAGS: 00010286
RAX: 0000000000000000 RBX: ffff888146bb8018 RCX: 0000000000000000
RDX: 0000000000000001 RSI: ffffffff88fdcb40 RDI: fffff5200030cf51
RBP: 0000000000000003 R08: 0000000000000001 R09: ffff8880ba04c1a7
R10: ffffed1017409834 R11: 0000000000000001 R12: 0000000000000000
R13: ffff888146bb8018 R14: ffffffff8c3b1740 R15: ffff88803118d798
FS:  0000000000000000(0000) GS:ffff8880ba100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ff333f8b158 CR3: 000000001db00000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 __refcount_sub_and_test include/linux/refcount.h:283 [inline]
 __refcount_dec_and_test include/linux/refcount.h:315 [inline]
 refcount_dec_and_test include/linux/refcount.h:333 [inline]
 kref_put include/linux/kref.h:64 [inline]
 nfc_llcp_local_put net/nfc/llcp_core.c:183 [inline]
 nfc_llcp_local_put+0x155/0x1a0 net/nfc/llcp_core.c:178
 llcp_sock_destruct+0x5b/0x110 net/nfc/llcp_sock.c:942
 __sk_destruct+0x3f/0x730 net/core/sock.c:1795
 skb_release_head_state+0x71/0x1a0 net/core/skbuff.c:712
 skb_release_all net/core/skbuff.c:723 [inline]
 __kfree_skb net/core/skbuff.c:739 [inline]
 kfree_skb net/core/skbuff.c:757 [inline]
 kfree_skb+0xac/0x2c0 net/core/skbuff.c:751
 skb_queue_purge+0xb/0x20 net/core/skbuff.c:3133
 nfc_llcp_socket_release+0x2a/0x770 net/nfc/llcp_core.c:73
 local_cleanup+0x10/0xb0 net/nfc/llcp_core.c:155
 local_release net/nfc/llcp_core.c:174 [inline]
 kref_put include/linux/kref.h:65 [inline]
 nfc_llcp_local_put net/nfc/llcp_core.c:183 [inline]
 nfc_llcp_local_put+0x134/0x1a0 net/nfc/llcp_core.c:178
 llcp_sock_destruct+0x5b/0x110 net/nfc/llcp_sock.c:942
 __sk_destruct+0x3f/0x730 net/core/sock.c:1795
 sock_put include/net/sock.h:1803 [inline]
 llcp_sock_release+0x2fd/0x4a0 net/nfc/llcp_sock.c:644
 __sock_release+0xbb/0x270 net/socket.c:599
 sock_close+0xf/0x20 net/socket.c:1258
 __fput+0x209/0x870 fs/file_table.c:280
 task_work_run+0xc0/0x160 kernel/task_work.c:140
 exit_task_work include/linux/task_work.h:30 [inline]
 do_exit+0xa26/0x2500 kernel/exit.c:825
 do_group_exit+0xe7/0x290 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+0x35/0x40 kernel/exit.c:931
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7ff333f34b09
Code: Unable to access opcode bytes at RIP 0x7ff333f34adf.
RSP: 002b:00007ffe22b4b848 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 00007ff333fbf390 RCX: 00007ff333f34b09
RDX: 000000000000003c RSI: 00000000000000e7 RDI: 0000000000000000
RBP: 0000000000000000 R08: ffffffffffffffb8 R09: 0000000000000001
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ff333fbf390
R13: 0000000000000001 R14: 0000000000000000 R15: 0000000000000001