[PATCH] tools lib traceevent: Do not reassign parg after collapse_tree()

[PATCH] tools lib traceevent: Do not reassign parg after collapse_tree()

[Steven Rostedt]

At the end of process_filter(), collapse_tree() was changed to update the
parg parameter, but the reassignment after the call wasn't removed.
What happens is that the "current_op" gets modified and freed and parg
is assigned to the new allocated argument. But after the call to
collapse_tree(), parg is assigned again to the just freed "current_op",
and this causes the tool to crash.

current_op must also be assigned to NULL in case of error, otherwise it
will cause it to be free()ed twice.

Cc: Namhyung Kim <namhyung@kernel.org>
Cc: stable@vger.kernel.org # 3.14+
Fixes: 42d6194d133c ("tools lib traceevent: Refactor process_filter()")
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 tools/lib/traceevent/parse-filter.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/lib/traceevent/parse-filter.c b/tools/lib/traceevent/parse-filter.c
index 0144b3d1bb77..88cccea3ca99 100644
--- a/tools/lib/traceevent/parse-filter.c
+++ b/tools/lib/traceevent/parse-filter.c
@@ -1164,11 +1164,11 @@ process_filter(struct event_format *event, struct filter_arg **parg,
 		current_op = current_exp;
 
 	ret = collapse_tree(current_op, parg, error_str);
+	/* collapse_tree() may free current_op, and updates parg accordingly */
+	current_op = NULL;
 	if (ret < 0)
 		goto fail;
 
-	*parg = current_op;
-
 	free(token);
 	return 0;
 
-- 
1.8.3.1

Re: [PATCH] tools lib traceevent: Do not reassign parg after collapse_tree()

[Namhyung Kim]

Hi Steve,

On Thu, May 12, 2016 at 4:09 AM, Steven Rostedt <rostedt@goodmis.org> wrote:
>
> At the end of process_filter(), collapse_tree() was changed to update the
> parg parameter, but the reassignment after the call wasn't removed.
> What happens is that the "current_op" gets modified and freed and parg
> is assigned to the new allocated argument. But after the call to
> collapse_tree(), parg is assigned again to the just freed "current_op",
> and this causes the tool to crash.
>
> current_op must also be assigned to NULL in case of error, otherwise it
> will cause it to be free()ed twice.
>
> Cc: stable@vger.kernel.org # 3.14+
> Fixes: 42d6194d133c ("tools lib traceevent: Refactor process_filter()")
> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

Acked-by: Namhyung Kim <namhyung@kernel.org>

Thanks,
Namhyung


> ---
>  tools/lib/traceevent/parse-filter.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/tools/lib/traceevent/parse-filter.c b/tools/lib/traceevent/parse-filter.c
> index 0144b3d1bb77..88cccea3ca99 100644
> --- a/tools/lib/traceevent/parse-filter.c
> +++ b/tools/lib/traceevent/parse-filter.c
> @@ -1164,11 +1164,11 @@ process_filter(struct event_format *event, struct filter_arg **parg,
>                 current_op = current_exp;
>
>         ret = collapse_tree(current_op, parg, error_str);
> +       /* collapse_tree() may free current_op, and updates parg accordingly */
> +       current_op = NULL;
>         if (ret < 0)
>                 goto fail;
>
> -       *parg = current_op;
> -
>         free(token);
>         return 0;
>
> --
> 1.8.3.1
>



-- 
Thanks,
Namhyung

Re: [PATCH] tools lib traceevent: Do not reassign parg after collapse_tree()

[Arnaldo Carvalho de Melo]

Em Thu, May 12, 2016 at 09:57:13PM +0900, Namhyung Kim escreveu:
> Hi Steve,
> 
> On Thu, May 12, 2016 at 4:09 AM, Steven Rostedt <rostedt@goodmis.org> wrote:
> >
> > At the end of process_filter(), collapse_tree() was changed to update the
> > parg parameter, but the reassignment after the call wasn't removed.
> > What happens is that the "current_op" gets modified and freed and parg
> > is assigned to the new allocated argument. But after the call to
> > collapse_tree(), parg is assigned again to the just freed "current_op",
> > and this causes the tool to crash.
> >
> > current_op must also be assigned to NULL in case of error, otherwise it
> > will cause it to be free()ed twice.
> >
> > Cc: stable@vger.kernel.org # 3.14+
> > Fixes: 42d6194d133c ("tools lib traceevent: Refactor process_filter()")
> > Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
 
> Acked-by: Namhyung Kim <namhyung@kernel.org>

Thanks, applied to perf/urgent.

- Arnaldo

[tip:perf/urgent] tools lib traceevent: Do not reassign parg after collapse_tree()

[tip-bot for Steven Rostedt]

Commit-ID:  106b816cb46ebd87408b4ed99a2e16203114daa6
Gitweb:     http://git.kernel.org/tip/106b816cb46ebd87408b4ed99a2e16203114daa6
Author:     Steven Rostedt <rostedt@goodmis.org>
AuthorDate: Wed, 11 May 2016 15:09:36 -0400
Committer:  Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Thu, 12 May 2016 11:27:00 -0300

tools lib traceevent: Do not reassign parg after collapse_tree()

At the end of process_filter(), collapse_tree() was changed to update
the parg parameter, but the reassignment after the call wasn't removed.

What happens is that the "current_op" gets modified and freed and parg
is assigned to the new allocated argument. But after the call to
collapse_tree(), parg is assigned again to the just freed "current_op",
and this causes the tool to crash.

The current_op variable must also be assigned to NULL in case of error,
otherwise it will cause it to be free()ed twice.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: stable@vger.kernel.org # 3.14+
Fixes: 42d6194d133c ("tools lib traceevent: Refactor process_filter()")
Link: http://lkml.kernel.org/r/20160511150936.678c18a1@gandalf.local.home
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/lib/traceevent/parse-filter.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/lib/traceevent/parse-filter.c b/tools/lib/traceevent/parse-filter.c
index 0144b3d..88cccea 100644
--- a/tools/lib/traceevent/parse-filter.c
+++ b/tools/lib/traceevent/parse-filter.c
@@ -1164,11 +1164,11 @@ process_filter(struct event_format *event, struct filter_arg **parg,
 		current_op = current_exp;
 
 	ret = collapse_tree(current_op, parg, error_str);
+	/* collapse_tree() may free current_op, and updates parg accordingly */
+	current_op = NULL;
 	if (ret < 0)
 		goto fail;
 
-	*parg = current_op;
-
 	free(token);
 	return 0;