linux-kernel - Re: [PATCH -tip v2 4/8] perf-probe: Use _stext based address instead of the symbol name

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:	Mon, 03 Feb 2014 17:32:30 +0900
From:	Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>
To:	Namhyung Kim <namhyung@...nel.org>
Cc:	Arnaldo Carvalho de Melo <acme@...stprotocols.net>,
	Srikar Dronamraju <srikar@...ux.vnet.ibm.com>,
	David Ahern <dsahern@...il.com>, linux-kernel@...r.kernel.org,
	"Steven Rostedt (Red Hat)" <rostedt@...dmis.org>,
	Oleg Nesterov <oleg@...hat.com>,
	Ingo Molnar <mingo@...hat.com>,
	"David A. Long" <dave.long@...aro.org>,
	yrl.pp-manager.tt@...achi.com
Subject: Re: [PATCH -tip v2 4/8] perf-probe: Use _stext based address instead
 of the symbol name

(2014/02/03 16:49), Namhyung Kim wrote:
> On Wed, 29 Jan 2014 09:14:59 +0000, Masami Hiramatsu wrote:
>> diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
>> index 4a9f43b..120954b 100644
>> --- a/tools/perf/util/probe-event.c
>> +++ b/tools/perf/util/probe-event.c
>> @@ -387,6 +387,44 @@ static int add_module_to_probe_trace_events(struct probe_trace_event *tevs,
>>  	return ret;
>>  }
>>  
>> +/* Post processing the probe events */
>> +static int post_process_probe_trace_events(struct probe_trace_event *tevs,
>> +					   int ntevs, const char *module,
>> +					   bool uprobe)
>> +{
>> +	struct symbol *sym;
>> +	struct map *map;
>> +	unsigned long stext = 0;
>> +	char *tmp;
>> +	int i;
>> +
>> +	if (uprobe)
>> +		return add_exec_to_probe_trace_events(tevs, ntevs, module);
>> +
>> +	/* Note that currently _stext based probe is not for drivers */
>> +	if (module)
>> +		return add_module_to_probe_trace_events(tevs, ntevs, module);
>> +
>> +	sym = __find_kernel_function_by_name("_stext", &map);
> 
> Couldn't we just use kmap->ref_reloc_sym instead of the hard-coded
> "_stext"?  You might want to check the Adrian's recent kaslr fixes (now
> in tip/perf/urgent).

Yeah, I just found Adrian's work and this series must be updated for that,
because symbol's address is now based on the real (relocated) address.
OK, I'll try to use a symbol in ref_reloc_sym. ;) Thank you for pointed it out!

Thanks!

-- 
Masami HIRAMATSU
IT Management Research Dept. Linux Technology Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu.pt@...achi.com


--
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/