------------[ cut here ]------------
refcount_t: addition on 0; use-after-free.
WARNING: CPU: 1 PID: 9424 at lib/refcount.c:25 refcount_warn_saturate+0x169/0x1e0 lib/refcount.c:25
Modules linked in:
CPU: 1 PID: 9424 Comm: kworker/u16:4 Not tainted 5.12.0-rc1-syzkaller #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-2 04/01/2014
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 a7 30 b0 fd 84 db 0f 85 36 ff ff ff e8 ba 28 b0 fd 48 c7 c7 60 ad be 89 c6 05 9f 17 ef 09 01 e8 53 57 ff 04 <0f> 0b e9 17 ff ff ff e8 9b 28 b0 fd 0f b6 1d 84 17 ef 09 31 ff 89
RSP: 0018:ffffc90003a079f8 EFLAGS: 00010086
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: ffff888072fd4080 RSI: ffffffff815bb195 RDI: fffff52000740f31
RBP: 0000000000000002 R08: 0000000000000000 R09: 0000000000000000
R10: ffffffff815b423e R11: 0000000000000000 R12: ffff888040816040
R13: ffff88801b2b0800 R14: ffff888013388330 R15: ffff888013388334
FS:  0000000000000000(0000) GS:ffff88802cb00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000004e4982 CR3: 000000006e428000 CR4: 0000000000150ee0
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:201 [inline]
 qrtr_node_lookup net/qrtr/qrtr.c:394 [inline]
 qrtr_send_resume_tx net/qrtr/qrtr.c:1004 [inline]
 qrtr_recvmsg+0x84a/0x980 net/qrtr/qrtr.c:1067
 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