linux-kernel - Re: RFC: introduce struct ksymbol

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Tue, 14 Apr 2009 23:14:11 -0700
From:	Joe Perches <joe@...ches.com>
To:	Ingo Molnar <mingo@...e.hu>
Cc:	Sam Ravnborg <sam@...nborg.org>,
	Rusty Russell <rusty@...tcorp.com.au>,
	Frederic Weisbecker <fweisbec@...il.com>,
	Steven Rostedt <rostedt@...dmis.org>,
	Zhaolei <zhaolei@...fujitsu.com>,
	Tom Zanussi <tzanussi@...il.com>,
	Li Zefan <lizf@...fujitsu.com>,
	LKML <linux-kernel@...r.kernel.org>,
	Andrew Morton <akpm@...ux-foundation.org>
Subject: Re: RFC: introduce struct ksymbol

On Wed, 2009-04-15 at 07:58 +0200, Ingo Molnar wrote:
> (Sam and Rusty Cc:-ed)
> > Perhaps a conversion from
> > 
> > "char str[KSYM_SYMBOL_LEN]"
> > to
> > "struct ksymbol sym"?
> > 
> > could be useful.
> > 
> > There are a few places that use a hard coded length of 128
> > instead of KSYM_SYMBOL_LENGTH that are also converted.
> > 
> > Compile tested only
> 
> Why not 'struct ksym'? That name is unused right now, it is shorter 
> and just as descriptive.

Either's ok with me.

> Downsides would be loss of awareness of stack footprint impact. A 
> plain struct is easy to slap on, and it's not immediately visible 
> that it carries 128 bytes of weight.

Stack footprint with KSYM_SYMBOL_LEN isn't very apparent.
KSYM_SYMBOL_LEN is more than 200.

 #define KSYM_NAME_LEN 128
 #define KSYM_SYMBOL_LEN (sizeof("%s+%#lx/%#lx [%s]") + (KSYM_NAME_LEN - 1) + \
                         2*(BITS_PER_LONG*3/10) + (MODULE_NAME_LEN - 1) + 1)
 
> It might also be confusing in 
> terms of the nature of the interface - whether it's a pointery 
> object or not.

Specified type makes it hard to pass the wrong
sized buffer.

> Prior use:
>         char str[KSYM_SYMBOL_LEN];
>         kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
> New use:
> 	struct ksym sym;
> 	kallsyms_lookup(rec->ip, NULL, NULL, NULL, &sym);

cheers, Joe

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/