Re: [PATCH] perf tools: Fix possible double free on error
From: Masami Hiramatsu
Date: Wed Mar 04 2015 - 07:47:14 EST
(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;
>
--
Masami HIRAMATSU
Software Platform Research Dept. Linux Technology Research Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu.pt@xxxxxxxxxxx
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