------------[ cut here ]------------
refcount_t: addition on 0; use-after-free.
WARNING: CPU: 0 PID: 566 at lib/refcount.c:25 refcount_warn_saturate+0x169/0x1e0 lib/refcount.c:25
Modules linked in:
CPU: 0 PID: 566 Comm: kworker/u4:5 Not tainted 5.14.0-rc5-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 27 32 9f fd 84 db 0f 85 36 ff ff ff e8 da 2b 9f fd 48 c7 c7 20 71 e3 89 c6 05 75 8a 81 09 01 e8 41 c5 11 05 <0f> 0b e9 17 ff ff ff e8 bb 2b 9f fd 0f b6 1d 5a 8a 81 09 31 ff 89
RSP: 0018:ffffc90002c3fa00 EFLAGS: 00010082
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: ffff888015fa9c40 RSI: ffffffff815d85c5 RDI: fffff52000587f32
RBP: 0000000000000002 R08: 0000000000000000 R09: 0000000000000000
R10: ffffffff815d23fe R11: 0000000000000000 R12: ffff8880155d0000
R13: ffff88805d30e400 R14: ffff888035dd8cb0 R15: ffff888035dd8cb4
FS:  0000000000000000(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000001899848 CR3: 00000000159b5000 CR4: 00000000001506f0
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:202 [inline]
 qrtr_node_lookup net/qrtr/qrtr.c:398 [inline]
 qrtr_send_resume_tx net/qrtr/qrtr.c:999 [inline]
 qrtr_recvmsg+0x85a/0x990 net/qrtr/qrtr.c:1067
 sock_recvmsg_nosec net/socket.c:943 [inline]
 sock_recvmsg net/socket.c:961 [inline]
 sock_recvmsg net/socket.c:957 [inline]
 kernel_recvmsg+0x110/0x160 net/socket.c:986
 qrtr_ns_worker+0x15a/0x1720 net/qrtr/ns.c:684
 process_one_work+0x98d/0x1630 kernel/workqueue.c:2276
 worker_thread+0x658/0x11f0 kernel/workqueue.c:2422
 kthread+0x3e5/0x4d0 kernel/kthread.c:319
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
----------------
Code disassembly (best guess):
   0:	09 31                	or     %esi,(%rcx)
   2:	ff 89 de e8 27 32    	decl   0x3227e8de(%rcx)
   8:	9f                   	lahf   
   9:	fd                   	std    
   a:	84 db                	test   %bl,%bl
   c:	0f 85 36 ff ff ff    	jne    0xffffff48
  12:	e8 da 2b 9f fd       	callq  0xfd9f2bf1
  17:	48 c7 c7 20 71 e3 89 	mov    $0xffffffff89e37120,%rdi
  1e:	c6 05 75 8a 81 09 01 	movb   $0x1,0x9818a75(%rip)        # 0x9818a9a
  25:	e8 41 c5 11 05       	callq  0x511c56b
  2a:	0f 0b                	ud2     <-- trapping instruction
  2c:	e9 17 ff ff ff       	jmpq   0xffffff48
  31:	e8 bb 2b 9f fd       	callq  0xfd9f2bf1
  36:	0f b6 1d 5a 8a 81 09 	movzbl 0x9818a5a(%rip),%ebx        # 0x9818a97
  3d:	31 ff                	xor    %edi,%edi
  3f:	89                   	.byte 0x89