linux-kernel - Re: [PATCHv3 6/7] symbol lookup: use new kernel and module dereference functions

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Message-ID: <20171023083804.GA32339@tigerII.localdomain>
Date:   Mon, 23 Oct 2017 17:38:04 +0900
From:   Sergey Senozhatsky <sergey.senozhatsky@...il.com>
To:     Petr Mladek <pmladek@...e.com>
Cc:     Sergey Senozhatsky <sergey.senozhatsky.work@...il.com>,
        Sergey Senozhatsky <sergey.senozhatsky@...il.com>,
        Steven Rostedt <rostedt@...dmis.org>,
        Tony Luck <tony.luck@...el.com>,
        Fenghua Yu <fenghua.yu@...el.com>,
        Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Paul Mackerras <paulus@...ba.org>,
        Michael Ellerman <mpe@...erman.id.au>,
        James Bottomley <jejb@...isc-linux.org>,
        Helge Deller <deller@....de>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Jessica Yu <jeyu@...nel.org>,
        Alexei Starovoitov <ast@...nel.org>,
        linux-ia64@...r.kernel.org, linux-parisc@...r.kernel.org,
        linuxppc-dev@...ts.ozlabs.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCHv3 6/7] symbol lookup: use new kernel and module
 dereference functions

On (10/20/17 15:08), Petr Mladek wrote:
> On Thu 2017-10-19 15:42:35, Sergey Senozhatsky wrote:
> > Sorry for the delay and thanks for taking a look.
> > 
> > I'll try to re-spin the patch set by the end of this week/early next
> > week.
> > 
> > 
> > On (10/04/17 13:53), Petr Mladek wrote:
> > [..]
> > > Note that kallsyms_lookup() and module_address_lookup() is used
> > > in many other situations.
> > 
> > we dereference only things that can be dereferenced.
> > so calling it on already dereferenced address, or address
> > that does need to be dereferenced is OK.
> 
> My concern is that it changes the behavior. It will suddenly return
> another information for addresses that were not dereference before.

OK. I'd be really-really surprised to find out that anyone did
kallsyms_lookup()/module_address_lookup() on func descriptors,
but I understand your concerns. I'll try to keep everything
within vsprintf().

	-ss