[PATCH] perf lock: Fix a memory leak on an error path

zhaimingbing posted 1 patch 2 years ago
tools/perf/builtin-lock.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
[PATCH] perf lock: Fix a memory leak on an error path
Posted by zhaimingbing 2 years ago
if a strdup-ed string is NULL,the allocated memory needs freeing.

Signed-off-by: zhaimingbing <zhaimingbing@cmss.chinamobile.com>
---
 tools/perf/builtin-lock.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/tools/perf/builtin-lock.c b/tools/perf/builtin-lock.c
index b141f2134..086041bcb 100644
--- a/tools/perf/builtin-lock.c
+++ b/tools/perf/builtin-lock.c
@@ -2228,8 +2228,10 @@ static int __cmd_record(int argc, const char **argv)
 		else
 			ev_name = strdup(contention_tracepoints[j].name);
 
-		if (!ev_name)
+		if (!ev_name) {
+			free(rec_argv);
 			return -ENOMEM;
+		}
 
 		rec_argv[i++] = "-e";
 		rec_argv[i++] = ev_name;
-- 
2.33.0
Re: [PATCH] perf lock: Fix a memory leak on an error path
Posted by Peter Zijlstra 2 years ago
On Fri, Nov 24, 2023 at 05:26:57PM +0800, zhaimingbing wrote:
> if a strdup-ed string is NULL,the allocated memory needs freeing.
> 
> Signed-off-by: zhaimingbing <zhaimingbing@cmss.chinamobile.com>
> ---
>  tools/perf/builtin-lock.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/tools/perf/builtin-lock.c b/tools/perf/builtin-lock.c
> index b141f2134..086041bcb 100644
> --- a/tools/perf/builtin-lock.c
> +++ b/tools/perf/builtin-lock.c
> @@ -2228,8 +2228,10 @@ static int __cmd_record(int argc, const char **argv)
>  		else
>  			ev_name = strdup(contention_tracepoints[j].name);
>  
> -		if (!ev_name)
> +		if (!ev_name) {
> +			free(rec_argv);
>  			return -ENOMEM;
> +		}

Isn't this an error path straight into exit?
Re: [PATCH] perf lock: Fix a memory leak on an error path
Posted by Ingo Molnar 2 years ago
* Peter Zijlstra <peterz@infradead.org> wrote:

> On Fri, Nov 24, 2023 at 05:26:57PM +0800, zhaimingbing wrote:
> > if a strdup-ed string is NULL,the allocated memory needs freeing.
> > 
> > Signed-off-by: zhaimingbing <zhaimingbing@cmss.chinamobile.com>
> > ---
> >  tools/perf/builtin-lock.c | 4 +++-
> >  1 file changed, 3 insertions(+), 1 deletion(-)
> > 
> > diff --git a/tools/perf/builtin-lock.c b/tools/perf/builtin-lock.c
> > index b141f2134..086041bcb 100644
> > --- a/tools/perf/builtin-lock.c
> > +++ b/tools/perf/builtin-lock.c
> > @@ -2228,8 +2228,10 @@ static int __cmd_record(int argc, const char **argv)
> >  		else
> >  			ev_name = strdup(contention_tracepoints[j].name);
> >  
> > -		if (!ev_name)
> > +		if (!ev_name) {
> > +			free(rec_argv);
> >  			return -ENOMEM;
> > +		}
> 
> Isn't this an error path straight into exit?

It increases the quality of implementation if resources are free()d 
consistently regardless of whether the task is going to exit() immediately, 
for example it makes it easier to validate perf for the lack of memory 
leaks with Valgrind.

Thanks,

	Ingo
Re: [PATCH] perf lock: Fix a memory leak on an error path
Posted by Arnaldo Carvalho de Melo 2 years ago
Em Fri, Nov 24, 2023 at 01:56:35PM +0100, Ingo Molnar escreveu:
> 
> * Peter Zijlstra <peterz@infradead.org> wrote:
> 
> > On Fri, Nov 24, 2023 at 05:26:57PM +0800, zhaimingbing wrote:
> > > if a strdup-ed string is NULL,the allocated memory needs freeing.
> > > 
> > > Signed-off-by: zhaimingbing <zhaimingbing@cmss.chinamobile.com>
> > > ---
> > >  tools/perf/builtin-lock.c | 4 +++-
> > >  1 file changed, 3 insertions(+), 1 deletion(-)
> > > 
> > > diff --git a/tools/perf/builtin-lock.c b/tools/perf/builtin-lock.c
> > > index b141f2134..086041bcb 100644
> > > --- a/tools/perf/builtin-lock.c
> > > +++ b/tools/perf/builtin-lock.c
> > > @@ -2228,8 +2228,10 @@ static int __cmd_record(int argc, const char **argv)
> > >  		else
> > >  			ev_name = strdup(contention_tracepoints[j].name);
> > >  
> > > -		if (!ev_name)
> > > +		if (!ev_name) {
> > > +			free(rec_argv);
> > >  			return -ENOMEM;
> > > +		}
> > 
> > Isn't this an error path straight into exit?
> 
> It increases the quality of implementation if resources are free()d 
> consistently regardless of whether the task is going to exit() immediately, 
> for example it makes it easier to validate perf for the lack of memory 
> leaks with Valgrind.

I'm taking this positive comment about the patch as an Acked-by, ok?

- Arnaldo