Re: Solution (Re: [uml-devel] Re: Weird hostfs file corruption (mmap?))

[Henrik N. <hn...@ma...>]

On Sun, 27 Apr 2003, Matt Zimmerman wrote:

>       by MMAP_THRESHOLD) and if we can safely count on there being
>       at least one readable NUL byte after the end of the file's
>       contents.  This is true for all tested operating systems when
>       the file size is not an exact multiple of the page size.

Which is for good reasons.. not zeroing the remainder of the page is a 
security issue.

memset(buffer, 0, PAGE_CACHE_SIZE) just before the call to read_file 
in hostfs_readpage should address this problem I think.

Note: A quick inspection of the hostfs writepage function makes me think
there is another bug in flushing the last page of modified mmaped files
with an even page size.

Regards
Henrik