boot failure in 4.15-rc2 with afs in the trace

[Christoph Hellwig]

[    1.501264] BUG: unable to handle kernel NULL pointer dereference at 000000006714cfcb
[    1.502335] IP: rxrpc_release+0xd5/0x1c0
[    1.502865] PGD 0 P4D 0
[    1.503210] Oops: 0000 [#1] SMP
[    1.503589] Modules linked in:
[    1.503898] CPU: 5 PID: 1 Comm: swapper/0 Not tainted 4.15.0-rc2+ #226
[    1.504540] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014
[    1.505662] task: 00000000795f0d60 task.stack: 000000007d4309e4
[    1.506241] RIP: 0010:rxrpc_release+0xd5/0x1c0
[    1.506698] RSP: 0000:ffffc9000000be30 EFLAGS: 00010246
[    1.507217] RAX: 0000000000000000 RBX: ffff8800792c3b40 RCX: 0000000000000000
[    1.507919] RDX: 0000000000000001 RSI: ffff8800792a0e00 RDI: 0000000000000040
[    1.508621] RBP: ffff8800792c3c58 R08: 0000000000000000 R09: 0000000000000000
[    1.509326] R10: ffffc9000000be30 R11: 0000000000000010 R12: 0000000000000000
[    1.510065] R13: ffffffff82fb976e R14: 0000000000000000 R15: 0000000000000000
[    1.510767] FS:  0000000000000000(0000) GS:ffff88007fd40000(0000) knlGS:0000000000000000
[    1.511560] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[    1.512126] CR2: 0000000000000018 CR3: 0000000002833000 CR4: 00000000000006e0
[    1.512852] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[    1.513541] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[    1.514102] Call Trace:
[    1.514310]  sock_release+0x15/0x70
[    1.514596]  afs_open_socket+0x100/0x10b
[    1.514914]  afs_init+0x280/0x321
[    1.515185]  ? trace_event_define_fields_afs_call_state+0xe2/0xe2
[    1.515670]  do_one_initcall+0x39/0x160
[    1.515982]  ? set_debug_rodata+0xc/0xc
[    1.516290]  ? set_debug_rodata+0xc/0xc
[    1.516598]  kernel_init_freeable+0x112/0x193
[    1.516968]  ? rest_init+0xa0/0xa0
[    1.517243]  kernel_init+0x5/0xf0
[    1.517512]  ret_from_fork+0x1f/0x30
[    1.517800] Code: 48 8b 3d 27 5b 5d 01 e8 aa 25 28 ff 48 8d bb 00 01 00 00 e8 ce 07 01 00 48 8b 83 48 03 00 00 bf 40 00 00 00 48 8b 35 03 5b 5d 01 <48> 8b 50 18 48 83 c2 70 e8 2e 22 28 ff 48 8b 83 48 03 00 00 bf
[    1.519290] RIP: rxrpc_release+0xd5/0x1c0 RSP: ffffc9000000be30
[    1.519756] CR2: 0000000000000018
[    1.520036] ---[ end trace 388ed6258b8cbd77 ]---
[    1.520430] Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000009
[    1.520430]
[    1.521338] Kernel Offset: disabled
[    1.521631] ---[ end Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000009
[    1.521631]