Re: [PATCH] tools/thermal: Fix common realloc mistake

[zhangjiao2]

From: zhang jiao <zhangjiao2@xxxxxxxxxxxxxxxxxxxx>

On Fri, 8 Nov 2024 13:09 PM Rafael J. Wysocki
<Rafael J. Wysocki> wrote:
>>On Fri, Nov 8, 2024 at 7:39 AM zhangjiao2
>><zhangjiao2@xxxxxxxxxxxxxxxxxxxx> wrote:
>>
>> From: zhang jiao <zhangjiao2@xxxxxxxxxxxxxxxxxxxx>
>>
>> Do not set thermometer->tz NULL when realloc failed.

>Presumably, this fixes a problem.

>What problem does it fix?
Thermometer->tz is NULL when realloc failed.
This will cause memory leaks. 
We should use temporary variables to 
check the return value of realloc.

>> Signed-off-by: zhang jiao <zhangjiao2@xxxxxxxxxxxxxxxxxxxx>
>> ---
>>  tools/thermal/thermometer/thermometer.c | 6 ++++--
>>  1 file changed, 4 insertions(+), 2 deletions(-)
>>
>> diff --git a/tools/thermal/thermometer/thermometer.c b/tools/thermal/thermometer/thermometer.c
>> index 1a87a0a77f9f..e08291a97fd8 100644
>> --- a/tools/thermal/thermometer/thermometer.c
>> +++ b/tools/thermal/thermometer/thermometer.c
>> @@ -259,6 +259,7 @@ static int thermometer_add_tz(const char *path, const char *name, int polling,
>>  {
>>         int fd;
>>         char tz_path[PATH_MAX];
>> +       void *tmp;
>>
>>         sprintf(tz_path, CLASS_THERMAL"/%s/temp", path);
>>
>> @@ -268,12 +269,13 @@ static int thermometer_add_tz(const char *path, const char *name, int polling,
>>                 return -1;
>>         }
>>
>> -       thermometer->tz = realloc(thermometer->tz,
>> +       tmp = realloc(thermometer->tz,
>>                                   sizeof(*thermometer->tz) * (thermometer->nr_tz + 1));
>> -       if (!thermometer->tz) {
>> +       if (!tmp) {
>>                 ERROR("Failed to allocate thermometer->tz\n");
>>                 return -1;
>>         }
>> +       thermometer->tz = tmp;
>>
>>         thermometer->tz[thermometer->nr_tz].fd_temp = fd;
>>         thermometer->tz[thermometer->nr_tz].name = strdup(name);
-- 
2.33.0