------------[ cut here ]------------
refcount_t: addition on 0; use-after-free.
WARNING: CPU: 1 PID: 27 at lib/refcount.c:25 refcount_warn_saturate+0x169/0x1e0 lib/refcount.c:25
Modules linked in:
CPU: 1 PID: 27 Comm: kworker/u4:2 Not tainted 5.10.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: qrtr_ns_handler qrtr_ns_worker
RIP: 0010:refcount_warn_saturate+0x169/0x1e0 lib/refcount.c:25
Code: 09 31 ff 89 de e8 47 57 ba fd 84 db 0f 85 36 ff ff ff e8 2a 5f ba fd 48 c7 c7 40 2e 9d 89 c6 05 e4 c4 22 09 01 e8 b1 d8 f5 04 <0f> 0b e9 17 ff ff ff e8 0b 5f ba fd 0f b6 1d c9 c4 22 09 31 ff 89
RSP: 0018:ffffc90000e1f9f8 EFLAGS: 00010086
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: ffff888010f41a40 RSI: ffffffff8158e0c5 RDI: fffff520001c3f31
RBP: 0000000000000002 R08: 0000000000000001 R09: ffff8880b9f2005b
R10: 0000000000000000 R11: 0000000000000000 R12: ffff888140cb8000
R13: ffff888022a23c00 R14: ffff888022e29030 R15: ffff888022e29034
FS:  0000000000000000(0000) GS:ffff8880b9f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000001b636000 CR4: 00000000001526e0
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]
 kref_get include/linux/kref.h:45 [inline]
 qrtr_node_acquire net/qrtr/qrtr.c:196 [inline]
 qrtr_node_lookup net/qrtr/qrtr.c:389 [inline]
 qrtr_send_resume_tx net/qrtr/qrtr.c:981 [inline]
 qrtr_recvmsg+0x845/0x970 net/qrtr/qrtr.c:1044
 sock_recvmsg_nosec net/socket.c:885 [inline]
 sock_recvmsg net/socket.c:903 [inline]
 sock_recvmsg net/socket.c:899 [inline]
 kernel_recvmsg+0x110/0x160 net/socket.c:928
 qrtr_ns_worker+0x15a/0x1740 net/qrtr/ns.c:692
 process_one_work+0x933/0x15a0 kernel/workqueue.c:2272
 worker_thread+0x64c/0x1120 kernel/workqueue.c:2418
 kthread+0x3af/0x4a0 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296