Re: Race between vmtruncate and mapped areas?

Dave McCracken
2003-05-14T18:05:56Z

--On Wednesday, May 14, 2003 10:57:06 -0700 Andrew Morton <akpm@digeo.com>
wrote:

> yes. It's a very complex way of allocating anonymous memory.

Yep. And randomly, at that.

> I am told that Stephen, Linus and others discussed this at length at KS a
> couple of years ago and the upshot was that the application is racy anyway
> and there's nothing wrong with it.
>
> Hugh calls these "Morton pages" but it wasn't me and nobody saw me do it.
>
> It would be nice to make them go away - they cause problems.

Definitely. We almost have the pieces necessary to detect it and/or
prevent it, but the info isn't in quite the right layer at the right time.
If it weren't for the lock order problem with mmap_sem we could have nailed
it that way. Sigh.

Dave

======================================================================
Dave McCracken IBM Linux Base Kernel Team 1-512-838-3059
dmccr@us.ibm.com T/L 678-3059