RAX: ffffffffffffffda RBX: 00007fbe07bdf6d4 RCX: 0000000000455979
RDX: 000000002015bffc RSI: 0000000020343ff8 RDI: 00000000208deff8
RBP: 000000000072bea0 R08: 000000002000a000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000013
R13: 0000000000000440 R14: 00000000006fa6a0 R15: 0000000000000042
BUG: unable to handle kernel NULL pointer dereference at 0000000000000000
IP: strlen+0x45/0xa0 lib/string.c:482
PGD 800000014a009067 P4D 800000014a009067 PUD 1c1807067 PMD 0 
Oops: 0000 [#1] SMP PTI
Dumping ftrace buffer:
   (ftrace buffer empty)
Modules linked in:
CPU: 0 PID: 92 Comm: kworker/u4:4 Not tainted 4.16.0+ #87
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: rpciod rpc_async_schedule
RIP: 0010:strlen+0x45/0xa0 lib/string.c:482
RSP: 0000:ffff8801d8edf8f0 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: ffff8801522383e0 RSI: aaaaaaaaaaaab000 RDI: 0000000000000000
RBP: ffff8801d8edf920 R08: 00000000c04000d2 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff8801d84c4418
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff88021fc00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 00000001ab9a0000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 encode_rpcb_string net/sunrpc/rpcb_clnt.c:914 [inline]
 rpcb_enc_getaddr+0x2bb/0x5f0 net/sunrpc/rpcb_clnt.c:940
 rpcauth_wrap_req_encode net/sunrpc/auth.c:777 [inline]
 rpcauth_wrap_req+0x269/0x290 net/sunrpc/auth.c:791
 rpc_xdr_encode net/sunrpc/clnt.c:1754 [inline]
 call_transmit+0x9fc/0x1250 net/sunrpc/clnt.c:1949
 __rpc_execute+0x58c/0x1530 net/sunrpc/sched.c:784
 rpc_async_schedule+0x3b/0x50 net/sunrpc/sched.c:857
 process_one_work+0x12c6/0x1f60 kernel/workqueue.c:2113
 worker_thread+0x113c/0x24f0 kernel/workqueue.c:2247
 kthread+0x539/0x720 kernel/kthread.c:239
 ret_from_fork+0x35/0x40 arch/x86/entry/entry_64.S:406
Code: 8b 28 8b 80 88 0c 00 00 89 45 d4 4c 89 f3 eb 16 8b 7d d4 e8 4e 38 eb f7 eb 11 8b 3a e8 45 38 eb f7 eb 22 0f 1f 00 4d 85 ed 75 e5 <44> 0f b6 3b 48 89 df e8 2f 2b eb f7 0f b6 00 84 c0 74 07 f6 d0 
RIP: strlen+0x45/0xa0 lib/string.c:482 RSP: ffff8801d8edf8f0
CR2: 0000000000000000
---[ end trace ddf4b6d457be02cc ]---