BUG() in end_page_writeback(), stack overflows and system speed decrease with XFS over USB

[Juergen Urban]

On Saturday 21 November 2009 11:51:23 Michael Monnerie wrote:
> On Samstag, 21. November 2009 Juergen Urban wrote:
> > To get the error I just need to play video with mplayer and don't
> > need to write to the file system at all.
>
> This really sounds like a broken hardware. Have you tried running
> MEMTEST?
>
> mfg zmi

At the first moment I also thought that it is a hardware bug. I already ran 
MEMTEST for some hours, but it doesn't find anything. I replaced the main 
board, the CPU and the power supply. I also tried to replace/remove RAM. But 
I've done this while chasing for the stack overflow. But maybe this a problem 
which I introduced by replacing the hardware. So I will try to change all the 
hardware back.
Can someone explain the purpose of the BUG() in end_page_writeback()? Can I 
remove the line?
Will XFS also work if I disable all address operations? What is the purpose of 
the address operations?