------------[ cut here ]------------
refcount_t: underflow; use-after-free.
WARNING: CPU: 0 PID: 25304 at lib/refcount.c:28 refcount_warn_saturate+0x15b/0x1a0 lib/refcount.c:28
Modules linked in:
CPU: 0 PID: 25304 Comm: syz-executor.0 Not tainted 5.12.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:refcount_warn_saturate+0x15b/0x1a0 lib/refcount.c:28
Code: c7 00 db 71 8a 31 c0 e8 c3 6e 52 fd 0f 0b eb 85 e8 ea eb 85 fd c6 05 69 61 0a 0a 01 48 c7 c7 60 db 71 8a 31 c0 e8 a5 6e 52 fd <0f> 0b e9 64 ff ff ff e8 c9 eb 85 fd c6 05 49 61 0a 0a 01 48 c7 c7
RSP: 0018:ffffc90008f6fac8 EFLAGS: 00010246
RAX: 4c482cb134d3fc00 RBX: 0000000000000003 RCX: ffff88801e5b9c40
RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000
RBP: 0000000000000003 R08: ffffffff81653722 R09: ffffed1017345fe8
R10: ffffed1017345fe8 R11: 0000000000000000 R12: ffff88814454c018
R13: dffffc0000000000 R14: ffff88814454c000 R15: ffff888019a595a8
FS:  0000000002651400(0000) GS:ffff8880b9b00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f6e36271000 CR3: 000000002fbe8000 CR4: 00000000001506e0
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+0x226/0x230 net/nfc/llcp_core.c:183
 nfc_llcp_sock_free net/nfc/llcp_sock.c:1005 [inline]
 llcp_sock_destruct+0x1e3/0x2a0 net/nfc/llcp_sock.c:950
 __sk_destruct+0x4f/0x830 net/core/sock.c:1795
 skb_release_head_state+0xfb/0x210 net/core/skbuff.c:713
 skb_release_all net/core/skbuff.c:724 [inline]
 __kfree_skb+0x22/0x1d0 net/core/skbuff.c:740
 skb_queue_purge+0x131/0x1c0 net/core/skbuff.c:3134
 nfc_llcp_socket_release+0x34/0x8f0 net/nfc/llcp_core.c:73
 local_cleanup net/nfc/llcp_core.c:155 [inline]
 local_release net/nfc/llcp_core.c:174 [inline]
 kref_put include/linux/kref.h:65 [inline]
 nfc_llcp_local_put+0x16a/0x230 net/nfc/llcp_core.c:183
 nfc_llcp_sock_free net/nfc/llcp_sock.c:1005 [inline]
 llcp_sock_destruct+0x1e3/0x2a0 net/nfc/llcp_sock.c:950
 __sk_destruct+0x4f/0x830 net/core/sock.c:1795
 sock_put include/net/sock.h:1807 [inline]
 llcp_sock_release+0x374/0x480 net/nfc/llcp_sock.c:644
 __sock_release net/socket.c:599 [inline]
 sock_close+0xd8/0x260 net/socket.c:1258
 __fput+0x352/0x7b0 fs/file_table.c:280
 task_work_run+0x146/0x1c0 kernel/task_work.c:161
 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+0x10b/0x200 kernel/entry/common.c:208
 __syscall_exit_to_user_mode_work kernel/entry/common.c:290 [inline]
 syscall_exit_to_user_mode+0x26/0x70 kernel/entry/common.c:301
 do_syscall_64+0x4b/0xb0 arch/x86/entry/common.c:57
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x41940b
Code: 0f 05 48 3d 00 f0 ff ff 77 45 c3 0f 1f 40 00 48 83 ec 18 89 7c 24 0c e8 63 fc ff ff 8b 7c 24 0c 41 89 c0 b8 03 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 35 44 89 c7 89 44 24 0c e8 a1 fc ff ff 8b 44
RSP: 002b:00007ffce1970b10 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000005 RCX: 000000000041940b
RDX: ffffffffffffffbc RSI: 0000000008ec8c3a RDI: 0000000000000004
RBP: 0000000000000001 R08: 0000000000000000 R09: 0000001b2f021588
R10: 00007ffce1970c00 R11: 0000000000000293 R12: 000000000008b484
R13: 00000000000003e8 R14: 000000000056bf60 R15: 000000000008b460