Crashes on silk board

I can consistently produce a crash when shutting down the system
```
Unable to handle kernel NULL pointer dereference at virtual address 0000000d
pgd = c0003000
[0000000d] *pgd=80000040004003, *pmd=00000000
Stopping Weston reIfenrentcee Wayrlannda clom peorsirtoor..r.: Oops: 207 1 PREEMPT SMP ARM

Modules linked in: bc_example(O) dc_linuxfb(O) pvrsrvkm(O) [last unloaded: vspm]
CPU: 0 PID: 348 Comm: weston Tainted: G O 3.10.31-ltsi #1
task: d5488000 ti: d548a000 task.ti: d548a000
PC is at FreeBuf+0x28/0x27c [pvrsrvkm]
LR is at BM_Free+0x98/0xac [pvrsrvkm]
pc : [<bf009450>] lr : [<bf009e5c>] psr: 80030013
sp : d548bd58 ip : d548bd80 fp : d548bd7c
r10: 00000000 r9 : 00000000 r8 : 00000000
etc but the showdown hangs (sometimes!)
```
It seems to be more reliable if the ethernet isn't connected (maybe this relates to a known issue?) but the above happens even without ethernet.
I also get GDP hanging and doesn't get beyond the splash screen, it maybe that this more frequently happens on a reset rather than an initial boot.
Sometimes the mouse freezes at the top level screen (after returning from an app)