------------[ cut here ]------------
refcount_t: addition on 0; use-after-free.
WARNING: CPU: 1 PID: 53 at lib/refcount.c:25 refcount_warn_saturate+0x169/0x1e0 lib/refcount.c:25
Modules linked in:
CPU: 1 PID: 53 Comm: kworker/u4:2 Not tainted 5.12.0-rc4-next-20210325-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 b7 e1 a7 fd 84 db 0f 85 36 ff ff ff e8 fa da a7 fd 48 c7 c7 40 3e c2 89 c6 05 cd 99 e6 09 01 e8 da 5a fd 04 <0f> 0b e9 17 ff ff ff e8 db da a7 fd 0f b6 1d b2 99 e6 09 31 ff 89
RSP: 0018:ffffc90000f2f9f8 EFLAGS: 00010086
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: ffff888011f93900 RSI: ffffffff815c3fd5 RDI: fffff520001e5f31
RBP: 0000000000000002 R08: 0000000000000000 R09: 0000000000000000
R10: ffffffff815bd77e R11: 0000000000000000 R12: ffff8881401f0000
R13: ffff888025b76000 R14: ffff88802bcac7b0 R15: ffff88802bcac7b4
FS:  0000000000000000(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000001c5e708 CR3: 000000007c7ec000 CR4: 00000000001506e0
DR0: 00000000000000ff 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:201 [inline]
 qrtr_node_lookup net/qrtr/qrtr.c:394 [inline]
 qrtr_send_resume_tx net/qrtr/qrtr.c:1006 [inline]
 qrtr_recvmsg+0x85a/0x990 net/qrtr/qrtr.c:1074
 sock_recvmsg_nosec net/socket.c:888 [inline]
 sock_recvmsg net/socket.c:906 [inline]
 sock_recvmsg net/socket.c:902 [inline]
 kernel_recvmsg+0x110/0x160 net/socket.c:931
 qrtr_ns_worker+0x15a/0x1710 net/qrtr/ns.c:684
 process_one_work+0x98d/0x1600 kernel/workqueue.c:2275
 worker_thread+0x64c/0x1120 kernel/workqueue.c:2421
 kthread+0x3b1/0x4a0 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294