Re: [PATCH] perf tools: Fix possible double free on error

[He Kuang <hekuang@huawei.com>]

Hi,

It seems this patch not appeared in any repo, so ping..

On 2015/3/4 20:46, Masami Hiramatsu wrote:
> (2015/03/04 19:01), He Kuang wrote:
>> A double free occurred when get source file path failed. If lr->path
>> failed to assign a new value, it will be freed as the old path and then
>> be freed again during line_range__clear(), and causes this:
>>
>>    $ perf probe -L do_execve -k vmlinux
>>    *** Error in `/usr/bin/perf': double free or corruption (fasttop):
>>        0x0000000000a9ac50 ***
>>    ======= Backtrace: =========
>>    ../lib64/libc.so.6(+0x6eeef)[0x7ffff5e44eef]
>>    ../lib64/libc.so.6(+0x78cae)[0x7ffff5e4ecae]
>>    ../lib64/libc.so.6(+0x79987)[0x7ffff5e4f987]
>>    ../bin/perf[0x4ab41f]
>>    ...
>>
>> This patch fix this problem.
> Good catch!
>
> Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
>
> Thank you,
>
>> Signed-off-by: He Kuang <hekuang@huawei.com>
>> ---
>>   tools/perf/util/probe-event.c | 6 +++++-
>>   1 file changed, 5 insertions(+), 1 deletion(-)
>>
>> diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
>> index 919937e..7df30bd 100644
>> --- a/tools/perf/util/probe-event.c
>> +++ b/tools/perf/util/probe-event.c
>> @@ -650,7 +650,11 @@ static int __show_line_range(struct line_range *lr, const char *module)
>>   	/* Convert source file path */
>>   	tmp = lr->path;
>>   	ret = get_real_path(tmp, lr->comp_dir, &lr->path);
>> -	free(tmp);	/* Free old path */
>> +
>> +	/* Free old path when new path is assigned */
>> +	if (tmp != lr->path)
>> +		free(tmp);
>> +
>>   	if (ret < 0) {
>>   		pr_warning("Failed to find source file path.\n");
>>   		return ret;
>>
>