linux-kernel - Re: [PATCH 3/5] perf probe: Fix some error exit paths

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Date:	Tue, 18 May 2010 21:07:43 -0400
From:	Masami Hiramatsu <mhiramat@...hat.com>
To:	Arnaldo Carvalho de Melo <acme@...radead.org>
CC:	Ingo Molnar <mingo@...e.hu>, linux-kernel@...r.kernel.org,
	Arnaldo Carvalho de Melo <acme@...hat.com>,
	Frédéric Weisbecker <fweisbec@...il.com>,
	Mike Galbraith <efault@....de>,
	Paul Mackerras <paulus@...ba.org>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	Tom Zanussi <tzanussi@...il.com>
Subject: Re: [PATCH 3/5] perf probe: Fix some error exit paths

Arnaldo Carvalho de Melo wrote:
> From: Arnaldo Carvalho de Melo <acme@...hat.com>
> 
> That could leave filedescriptors open and leak memory. Also stop using
> xmalloc, use malloc and handle results just like other error cases in
> the same routine that used it.

Oops, thanks for fixing.
BTW, I found some other bugs... See below.

> 
> Cc: Frédéric Weisbecker <fweisbec@...il.com>
> Cc: Masami Hiramatsu <mhiramat@...hat.com>
> Cc: Mike Galbraith <efault@....de>
> Cc: Paul Mackerras <paulus@...ba.org>
> Cc: Peter Zijlstra <a.p.zijlstra@...llo.nl>
> Cc: Tom Zanussi <tzanussi@...il.com>
> LKML-Reference: <new-submission>
> Signed-off-by: Arnaldo Carvalho de Melo <acme@...hat.com>
> ---
>  tools/perf/util/probe-finder.c |   27 +++++++++++++++++----------
>  1 files changed, 17 insertions(+), 10 deletions(-)
> 
> diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
> index 93583eb..0bfd46a 100644
> --- a/tools/perf/util/probe-finder.c
> +++ b/tools/perf/util/probe-finder.c
> @@ -743,32 +743,34 @@ static int find_lazy_match_lines(struct list_head *head,
>  				 const char *fname, const char *pat)
>  {
>  	char *fbuf, *p1, *p2;
> -	int fd, ret, line, nlines = 0;
> +	int fd, line, nlines = -1;
>  	struct stat st;
>  
>  	fd = open(fname, O_RDONLY);
>  	if (fd < 0) {

I think "fd = -errno;" should be here.

>  		pr_warning("Failed to open %s: %s\n", fname, strerror(-fd));
> -		return fd;
> +		return -1;

Here is also better to return fd (= -errno).

>  	}
>  
> -	ret = fstat(fd, &st);
> -	if (ret < 0) {
> +	nlines = fstat(fd, &st);
> +	if (nlines < 0) {
>  		pr_warning("Failed to get the size of %s: %s\n",
>  			   fname, strerror(errno));
> -		return ret;
> +		goto out_close;
>  	}
> -	fbuf = xmalloc(st.st_size + 2);
> -	ret = read(fd, fbuf, st.st_size);
> -	if (ret < 0) {
> +	fbuf = malloc(st.st_size + 2);
> +	if (fbuf == NULL)

Here, we should set nlines = -ENOMEM;

> +		goto out_close;
> +	nlines = read(fd, fbuf, st.st_size);
> +	if (nlines < 0) {
>  		pr_warning("Failed to read %s: %s\n", fname, strerror(errno));
> -		return ret;
> +		goto out_free_fbuf;
>  	}
> -	close(fd);
>  	fbuf[st.st_size] = '\n';	/* Dummy line */
>  	fbuf[st.st_size + 1] = '\0';
>  	p1 = fbuf;
>  	line = 1;
> +	nlines = 0;
>  	while ((p2 = strchr(p1, '\n')) != NULL) {
>  		*p2 = '\0';
>  		if (strlazymatch(p1, pat)) {
> @@ -778,7 +780,10 @@ static int find_lazy_match_lines(struct list_head *head,
>  		line++;
>  		p1 = p2 + 1;
>  	}
> +out_free_fbuf:
>  	free(fbuf);
> +out_close:
> +	close(fd);
>  	return nlines;
>  }
>  
> @@ -955,6 +960,8 @@ int find_kprobe_trace_events(int fd, struct perf_probe_event *pev,
>  	if (!dbg) {
>  		pr_warning("No dwarf info found in the vmlinux - "
>  			"please rebuild with CONFIG_DEBUG_INFO=y.\n");
> +		free(pf.tevs);
> +		*tevs = NULL;
>  		return -EBADF;
>  	}
>  

Thank you,

-- 
Masami Hiramatsu
e-mail: mhiramat@...hat.com
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