Re: VirtualBox Hangs Pre-Init Due To Ext2FS Fault

[James Clarke]

I have now got a patch that drains down the queue, and it does successfully 
stop sblock from being dereferenced etc when we actually reload. However, 
sometimes thread 5 (the same one that would dereference sblock) seems to get 
stuck in vm_fault_continue (at least according to the kernel debugger), so I 
need to do some more debugging to see why.

James

> On 19 Jul 2015, at 15:00, Richard Braun <rbraun@sceen.net> wrote:
> 
>> On Sun, Jul 19, 2015 at 02:25:14PM +0100, James Clarke wrote:
>> Yeah, I tried inhibiting both buckets, but the paging RPCs still got 
>> through, so my guess was that libports's inhibit/resume methods weren't able 
>> to deal with libpager's own threads. The thing is I don't think we currently 
>> keep track of any reference to the main/worker threads, as 
>> pager_start_workers just takes a bucket and returns void. Is there a way we 
>> can instead make the main thread and/or workers able to block 
>> ports_inhibit_X_rpcs like normal RPC handlers and be cancelled etc? If 
>> possible I think that would be a cleaner solution.
> 
> To continue our discussion on IRC:
> 
> No, it would definitely not be a cleaner solution, just an ugly hack.
> Since paging doesn't occur as part of an RPC, you just can't use RPC
> stuff to manage it. I suggest building rwlock-based synrchonization
> functions specific to the pager workers.
> 
> -- 
> Richard Braun