[Q] How to set a page's protection from kernel land?

Inaky Perez Gonzalez (inaky@peloncho.fis.ucm.es)
Tue, 18 Aug 1998 13:51:02 +0200

Hi

I've been some hours trying to guess how to do this:

unsigned long pages;
pages = __get_free_pages (1, GFP_KERNEL);
mprotect (pages, 2*PAGE_SIZE, PROT_NONE);

from the kernel. Obviosuly, mprotect() should be sys_mprotect(), but
using it gives me a -EFAULT errno code. I'm afraid this is because the
page I've received with __get_free_pages() is not associated to any
current->mm MM context.

I need this to track a drunk pointer. I've developed an scheme
similar to that of Electric Fence within the kernel, but cannot manage
to set the protection. I've been lurking around linux/mm/mprotect.c
but cannot get anything clear.

Any help pls?

-- 


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