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Date: Fri, 06 Jul 2012 11:17:41 -0600
From: David Ahern <dsahern@gmail.com>
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To: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
CC: linux-kernel@vger.kernel.org, Ingo Molnar <mingo@kernel.org>,
        Steven Rostedt <rostedt@goodmis.org>
Subject: Re: [PATCH] perf lock: fix segfault with info subcommand following
 move to libtraceevent
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On 7/6/12 11:14 AM, Arnaldo Carvalho de Melo wrote:
> Em Fri, Jul 06, 2012 at 10:02:18AM -0600, David Ahern escreveu:
>> +++ b/tools/perf/builtin-lock.c
>> @@ -877,6 +877,9 @@ static int read_events(void)
>>   	if (!session)
>>   		die("Initializing perf session failed\n");
>>
>> +	if (!perf_session__has_traces(session, "lock record"))
>> +		exit(1);
>> +
>>   	return perf_session__process_events(session, &eops);
>>   }
>
> This is getting out of hand, first a die(), then an exit(1) and finally
> this function returns a value, ouch.
>
> I'd rather use return to signal that something went wrong and as well
> print some helpful warning to the user.
>
> Eventually we should fix all the other offenders, but lets try not to
> add even more.

Agree. But....

>
> Can you please resend with a pr_warning + return failure?


This command needs some love. The rc is not checked and requires some 
rework. e.g., the report path:

     setup_pager();
     select_key();
     read_events();    <---- the function I changed
     sort_result();
     print_result();

and the info path:
         setup_pager();
         read_events();
         dump_info();

I figured for 3.5 at least not segfault; clean up for 3.6 or later.

David