[PATCHv3 20/29] tools lib traceevent: Remove malloc_or_die from plugin_function.c

Jiri Olsa
2013-11-29T10:37:40Z

On Fri, Nov 29, 2013 at 03:41:10PM +0900, Namhyung Kim wrote:
> Hi Jiri,
>
> On Thu, 28 Nov 2013 12:33:19 +0100, Jiri Olsa wrote:
> > Removing malloc_or_die calls from plugin_function.c,
> > replacing them with standard malloc and error path.
> >
> > Suggested-by: Namhyung Kim <namhyung@kernel.org>
> > Signed-off-by: Jiri Olsa <jolsa@redhat.com>
> > Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
> > Cc: Frederic Weisbecker <fweisbec@gmail.com>
> > Cc: Ingo Molnar <mingo@elte.hu>
> > Cc: Namhyung Kim <namhyung@kernel.org>
> > Cc: Paul Mackerras <paulus@samba.org>
> > Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
> > Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
> > Cc: Steven Rostedt <rostedt@goodmis.org>
> > Cc: David Ahern <dsahern@gmail.com>
> > ---
> > tools/lib/traceevent/plugin_function.c | 15 +++++++++++++--
> > 1 file changed, 13 insertions(+), 2 deletions(-)
> >
> > diff --git a/tools/lib/traceevent/plugin_function.c b/tools/lib/traceevent/plugin_function.c
> > index 87acf9c..328d17d 100644
> > --- a/tools/lib/traceevent/plugin_function.c
> > +++ b/tools/lib/traceevent/plugin_function.c
> > @@ -44,10 +44,16 @@ static void add_child(struct func_stack *stack, const char *child, int pos)
> > free(stack->stack[pos]);
> > else {
> > if (!stack->stack)
> > - stack->stack = malloc_or_die(sizeof(char *) * STK_BLK);
> > + stack->stack = malloc(sizeof(char *) * STK_BLK);
> > else
> > stack->stack = realloc(stack->stack, sizeof(char *) *
> > (stack->size + STK_BLK));
>
> I think single realloc() can handle both cases. And this code has a
> problem that it overwrites stack->stack to NULL in case of error so that
> we cannot point original region anymore. You'd better to use a temp
> variable IMHO.

right you are, please check v3 attached..

thanks,
jirka

---
Removing malloc_or_die calls from plugin_function.c,
replacing them and factoring the code with standard
realloc and error path.

Suggested-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: David Ahern <dsahern@gmail.com>
---
tools/lib/traceevent/plugin_function.c | 25 ++++++++++++++++---------
1 file changed, 16 insertions(+), 9 deletions(-)

diff --git a/tools/lib/traceevent/plugin_function.c b/tools/lib/traceevent/plugin_function.c
index 87acf9c..b43cade 100644
--- a/tools/lib/traceevent/plugin_function.c
+++ b/tools/lib/traceevent/plugin_function.c
@@ -43,11 +43,17 @@ static void add_child(struct func_stack *stack, const char *child, int pos)
if (pos < stack->size)
free(stack->stack[pos]);
else {
- if (!stack->stack)
- stack->stack = malloc_or_die(sizeof(char *) * STK_BLK);
- else
- stack->stack = realloc(stack->stack, sizeof(char *) *
- (stack->size + STK_BLK));
+ char **ptr;
+
+ ptr = realloc(stack->stack, sizeof(char *) *
+ (stack->size + STK_BLK));
+ if (!ptr) {
+ warning("could not allocate plugin memory\n");
+ return;
+ }
+
+ stack->stack = ptr;
+
for (i = stack->size; i < stack->size + STK_BLK; i++)
stack->stack[i] = NULL;
stack->size += STK_BLK;
@@ -64,10 +70,11 @@ static int add_and_get_index(const char *parent, const char *child, int cpu)
return 0;

if (cpu > cpus) {
- if (fstack)
- fstack = realloc(fstack, sizeof(*fstack) * (cpu + 1));
- else
- fstack = malloc_or_die(sizeof(*fstack) * (cpu + 1));
+ fstack = realloc(fstack, sizeof(*fstack) * (cpu + 1));
+ if (!fstack) {
+ warning("could not allocate plugin memory\n");
+ return 0;
+ }

/* Account for holes in the cpu count */
for (i = cpus + 1; i <= cpu; i++)
--
1.8.3.1