linux-kernel - Re: module: save load_info for livepatch modules

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Date:	Fri, 13 Nov 2015 13:56:08 +0100 (CET)
From:	Miroslav Benes <mbenes@...e.cz>
To:	Jessica Yu <jeyu@...hat.com>
cc:	Josh Poimboeuf <jpoimboe@...hat.com>,
	Petr Mladek <pmladek@...e.com>,
	Rusty Russell <rusty@...tcorp.com.au>,
	Seth Jennings <sjenning@...hat.com>,
	Jiri Kosina <jikos@...nel.org>,
	Vojtech Pavlik <vojtech@...e.com>, linux-api@...r.kernel.org,
	live-patching@...r.kernel.org, x86@...nel.org,
	linux-kernel@...r.kernel.org
Subject: Re: module: save load_info for livepatch modules

On Fri, 13 Nov 2015, Miroslav Benes wrote:

> I agree this seems like the best approach. So if we preserve 
> mod_arch_syminfo (in case of s390) we should free it not in 
> module_finalize, but somewhere in free_module... where 
> module_arch_cleanup() is called... and also module_arch_freeing_init() is 
> called there too. And what you find there for s390 is 
> 
> 	vfree(mod->arch.syminfo);
> 	mod->arch.syminfo = NULL;
> 
> Well, it does nothing here, because mod->arch.syminfo is already NULL. It 
> was freed in module_finalize. So we can even remove this code from 
> module_finalize and all should be fine. At least for s390.

Which is not true because module_arch_freeing_init is also called from 
do_init_module, called from load_module. So we should move it to 
module_arch_cleanup.

That code is like a maze without Ariadne's thread.

Miroslav
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