------------[ cut here ]------------
refcount_t: underflow; use-after-free.
WARNING: CPU: 0 PID: 13545 at lib/refcount.c:28 refcount_warn_saturate+0x1d1/0x1e0 lib/refcount.c:28
Modules linked in:
CPU: 0 PID: 13545 Comm: syz-executor.1 Not tainted 5.12.0-rc7-syzkaller #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-2 04/01/2014
RIP: 0010:refcount_warn_saturate+0x1d1/0x1e0 lib/refcount.c:28
Code: e9 db fe ff ff 48 89 df e8 fc c6 ed fd e9 8a fe ff ff e8 c2 97 aa fd 48 c7 c7 c0 47 c1 89 c6 05 64 32 e8 09 01 e8 b4 a4 f9 04 <0f> 0b e9 af fe ff ff 0f 1f 84 00 00 00 00 00 41 56 41 55 41 54 55
RSP: 0018:ffffc90000c07b10 EFLAGS: 00010286
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: ffff88807751a180 RSI: ffffffff815b8155 RDI: fffff52000180f54
RBP: 0000000000000003 R08: 0000000000000000 R09: 0000000000000000
R10: ffffffff815b0ebe R11: 0000000000000000 R12: 0000000000000000
R13: ffff888015f48018 R14: ffffffff8da9fb80 R15: ffff88802a4d5178
FS:  000000000274a400(0000) GS:ffff88802ca00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f6846a48a70 CR3: 0000000076948000 CR4: 0000000000150ef0
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+0x1ab/0x200 net/nfc/llcp_core.c:178
 llcp_sock_destruct+0x81/0x150 net/nfc/llcp_sock.c:950
 __sk_destruct+0x4b/0x900 net/core/sock.c:1795
 sk_destruct+0xbd/0xe0 net/core/sock.c:1839
 __sk_free+0xef/0x3d0 net/core/sock.c:1850
 sock_wfree+0x129/0x240 net/core/sock.c:2074
 skb_release_head_state+0x9f/0x250 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+0xfa/0x3f0 net/core/skbuff.c:751
 skb_queue_purge+0x14/0x30 net/core/skbuff.c:3133
 nfc_llcp_socket_release+0x2e/0x870 net/nfc/llcp_core.c:73
 local_cleanup+0x18/0xb0 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+0x18c/0x200 net/nfc/llcp_core.c:178
 llcp_sock_destruct+0x81/0x150 net/nfc/llcp_sock.c:950
 __sk_destruct+0x4b/0x900 net/core/sock.c:1795
 sk_destruct+0xbd/0xe0 net/core/sock.c:1839
 __sk_free+0xef/0x3d0 net/core/sock.c:1850
 sk_free+0x78/0xa0 net/core/sock.c:1861
 sock_put include/net/sock.h:1807 [inline]
 llcp_sock_release+0x3c9/0x580 net/nfc/llcp_sock.c:644
 __sock_release+0xcd/0x280 net/socket.c:599
 sock_close+0x18/0x20 net/socket.c:1258
 __fput+0x288/0x920 fs/file_table.c:280
 task_work_run+0xdd/0x1a0 kernel/task_work.c:140
 tracehook_notify_resume include/linux/tracehook.h:189 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:174 [inline]
 exit_to_user_mode_prepare+0x249/0x250 kernel/entry/common.c:208
 __syscall_exit_to_user_mode_work kernel/entry/common.c:290 [inline]
 syscall_exit_to_user_mode+0x19/0x60 kernel/entry/common.c:301
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x41926b
Code: Unable to access opcode bytes at RIP 0x419241.
RSP: 002b:00007fff9e1d46a0 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000005 RCX: 000000000041926b
RDX: 0000000000570af0 RSI: 0000000000000081 RDI: 0000000000000004
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000570af0
R13: 00007fff9e1d47c0 R14: 000000000056bf60 R15: 0000000000065485