Messages in this thread | | | From | Rusty Russell <> | Subject | Re: Undoing module RONX protection fix | Date | Wed, 27 Apr 2011 14:42:34 +0930 |
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On Thu, 21 Apr 2011 16:19:49 +0200, Jan Glauber <jang@linux.vnet.ibm.com> wrote: > On Mon, Apr 18, 2011 at 08:13:36PM +0930, Rusty Russell wrote: > > On Mon, 18 Apr 2011 11:23:48 +0200, Jan Glauber <jang@linux.vnet.ibm.com> wrote: > > > While debugging I stumbled over two problems in the code that protects module > > > pages. > > > > > > First issue is that disabling the protection before freeing init or unload of > > > a module is not symmetric with the enablement. For instance, if pages are set > > > to RO the page range from module_core to module_core + core_ro_size is > > > protected. If a module is unloaded the page range from module_core to > > > module_core + core_size is set back to RW. > > > So pages that were not set to RO are also changed to RW. > > > This is not critical but IMHO it should be symmetric. > > > > > > Second issue is that while set_memory_rw & set_memory_ro are used for > > > RO/RW changes only set_memory_nx is involved for NX/X. One would await that > > > the inverse function is called when the NX protection should be removed, > > > which is not the case here, unless I'm missing something. > > > > > > The following patch addresses both issues. Works on s390. Boot tested on x86. > > > > > > Please comment, > > > > Applied, minus the S/390 EXPORT_SYMBOL which Christoph pointed out. I > > turned your mail into the commit message, since it was clearer and more > > verbose. I don't see why they would be different. > > There's a bug in my patch which just killed one of my s390 machines. > Can you merge this with the previuos patch?
Hmm...
Applied, but that function is really kind of silly. We should probably just split into unset_section_ro_nx() into unset_module_init_ro_nx() and unset_module_core_ro_nx().
(And why isn't that function static anyway?)
Patch appreciated :) Rusty.
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