Re: Crashes if running WordPerfect 5.1

[Stas Sergeev <stsp@aknet.ru>]

Hello.

Bart Oldeman wrote:
> mremap is behaving consistently (i.e. if you mmap bytes 4096-8191 of a
> file with size 4000 you can't expect that file to be extended to 8192
> bytes, the same is true for shm virtual files.
I just think kernel must hide that
things from userspace and resolve
them internally. "man mmap" says:
---
  MAP_ANONYMOUS
               The mapping is not backed by any file
---
So there should be no considerations
about a file resizing on a userspace.
For userspace it must behave as if there
is no file involved, otherwise it
contradicts with docs I think.

What I was thinking about a cheap
work around, is probably to allocate
the new region the way your hack does,
but then, instead of memcpy(), still
use mremap() MREMAP_FIXED to remap the
old region to the beginning of the new one.
This will preserve the aliases, but will
probably not work reliably... at least
that looks extremely risky to do.