diff --git a/js/src/util/NativeStack.cpp b/js/src/util/NativeStack.cpp
index 4e4189d3978..e77289c318a 100644
--- a/js/src/util/NativeStack.cpp
+++ b/js/src/util/NativeStack.cpp
@@ -95,17 +95,16 @@ void* js::GetNativeStackBaseImpl() {
   pthread_t thread = pthread_self();
   pthread_attr_t sattr;
   pthread_attr_init(&sattr);
-  pthread_getattr_np(thread, &sattr);
+  int rc = pthread_getattr_np(thread, &sattr);
+  MOZ_RELEASE_ASSERT(rc == 0, "pthread_getattr_np failed");
 
   // stackBase will be the *lowest* address on all architectures.
   void* stackBase = nullptr;
   size_t stackSize = 0;
-  int rc = pthread_attr_getstack(&sattr, &stackBase, &stackSize);
-  if (rc) {
-    MOZ_CRASH(
-        "call to pthread_attr_getstack failed, unable to setup stack range for "
-        "JS");
-  }
+  rc = pthread_attr_getstack(&sattr, &stackBase, &stackSize);
+  MOZ_RELEASE_ASSERT(rc == 0,
+                     "call to pthread_attr_getstack failed, unable to setup "
+                     "stack range for JS");
   MOZ_RELEASE_ASSERT(stackBase,
                      "invalid stack base, unable to setup stack range for JS");
   pthread_attr_destroy(&sattr);
@@ -148,7 +147,8 @@ void* js::GetNativeStackBaseImpl() {
    * FIXME: this function is non-portable;
    * other POSIX systems may have different np alternatives
    */
-  pthread_getattr_np(thread, &sattr);
+  MOZ_RELEASE_ASSERT(pthread_getattr_np(thread, &sattr) == 0,
+                     "pthread_getattr_np failed");
 #    endif
 
   void* stackBase = 0;
diff --git a/mozglue/misc/StackWalk.cpp b/mozglue/misc/StackWalk.cpp
index 7216a62fe9c..cc62b4d7859 100644
--- a/mozglue/misc/StackWalk.cpp
+++ b/mozglue/misc/StackWalk.cpp
@@ -949,7 +949,8 @@ MFBT_API void MozStackWalk(MozWalkStackCallback aCallback,
 #    elif defined(ANDROID)
   pthread_attr_t sattr;
   pthread_attr_init(&sattr);
-  pthread_getattr_np(pthread_self(), &sattr);
+  int rc = pthread_getattr_np(pthread_self(), &sattr);
+  MOZ_RELEASE_ASSERT(rc == 0, "pthread_getattr_np failed");
   void* stackBase = stackEnd = nullptr;
   size_t stackSize = 0;
   if (gettid() != getpid()) {