Re: Undoing module RONX protection fix

[Jan Glauber <jang@linux.vnet.ibm.com>]

On Thu, Apr 28, 2011 at 09:06:39PM +0930, Rusty Russell wrote:
> On Thu, 28 Apr 2011 12:08:20 +0200, Jan Glauber <jang@linux.vnet.ibm.com> wrote:
> > How about this?
> > 
> > To be honest I don't like the inverse naming like in unset no-execute
> > too much, it makes me feel dizzy. But I wanted to keep the changes
> > minimal.
> 
> Yes, it should probably just be called protect_module_pages and
> unprotect_module_pages.  The current names provide far too much
> information.
> 
> But going back a bit, how did we end up with a NULL mod->module_init and
> yet module->init_text_size, mod->init_size or mod->init_ro_size
> non-zero?

printk'ing this reveals that mod->init_ro_size is not 0 but 0x1000.
Therefore the first page was modified.

Looks like init_ro_size is missing the reset to zero at the end of the init_module
syscall. Next patch ? ;-

> Because if start == end, set_page_attributes() is a noop, right?

Right.

> Confused,
> Rusty.
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