[Pkg-uml-pkgs] Bug#410154: checking /dev/shm inside a chroot

[bdb at forbidden.co.uk]

On Thu, Feb 08, 2007 at 07:37:26PM +0100, Mattia Dongili wrote:
> Hello!
> 
> > Ok, I guess the bug should be that one doesn't get a good warning message
> > when a mmap fails because of size limits on /dev/shm.
> 
> I don't think it's that obvious. The mmap actually succeed, the real
> problem is the filesystem becomes full after some (in your case short)
> time.
> See also http://user-mode-linux.sourceforge.net/new/problems.html#sigbus
> 

Ah, oh well, not catchable there then....

Perhaps a reasonable fix would be in the uml code at the start that checks
/dev/shm, and prints that message.

It should just statfs it and bomb out or give a big warning if the free space is
less than the selected memory size.

That could still go wrong because of the lazy build up to full use of
the memory, with multiple instances but at least it would give an easy
diagnosis for my case, where the free space is infeasibly small.

-- 
Brian_Brunswick__bdb at forbidden.co.uk__Video_Software_Architect____Disclaimer