Subject: Re: kernel mappings of shared-library pages
To: None <>
From: Bill Sommerfeld <>
List: tech-kern
Date: 10/13/2001 12:18:11
> While working on a fix for pr/13998 I noticed that several (maybe many) 
> shared library pages seem to be permanently mapped into the kernel.  This 
> is bad news on a VAC machine since such mappings tend to be always 
> writable, so we must leave all such mappings of that page uncached (all 
> user-space mappings are read-only).
> ... any idea where they may be being entered?

One guess: left-over UBC mappings; both a.out and ELF do a
read(2) of the file header to find out how much to mmap.

It might be more efficient overall for the run-time linker to mmap the
whole file read-only and then trim back based on the the header.

						- Bill