pthread : Add null check at pthread_getstacksize

Without this condition, null dereference assert will occur

diff --git a/lib/libc/pthread/pthread_attrgetstacksize.c b/lib/libc/pthread/pthread_attrgetstacksize.c
index 605a45e..415ef01 100644 (file)
--- a/lib/libc/pthread/pthread_attrgetstacksize.c
+++ b/lib/libc/pthread/pthread_attrgetstacksize.c
@@ -106,7 +106,7 @@ int pthread_attr_getstacksize(FAR const pthread_attr_t *attr, FAR long *stacksiz
 
        sdbg("attr=0x%p stacksize=0x%p\n", attr, stacksize);
 
-       if (!stacksize) {
+       if (!attr || !stacksize) {
                ret = EINVAL;
        } else {
                *stacksize = attr->stacksize;