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

[He Kuang]

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@xxxxxxxxxxx>
>
> Thank you,
>
> > Signed-off-by: He Kuang <hekuang@xxxxxxxxxx>
> > ---
> >   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;


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