diff --git a/Libraries/LibPthread/pthread.cpp b/Libraries/LibPthread/pthread.cpp
index ada649f0a5..56436b1e89 100644
--- a/Libraries/LibPthread/pthread.cpp
+++ b/Libraries/LibPthread/pthread.cpp
@@ -537,21 +537,15 @@ int pthread_setspecific(pthread_key_t key, const void* value)
     t_specifics.values[key] = const_cast<void*>(value);
     return 0;
 }
-int pthread_setname_np(pthread_t thread, const char* buffer, int buffer_size)
+int pthread_setname_np(pthread_t thread, const char* name)
 {
-    if (buffer_size < 0) {
-        errno = EINVAL;
-        return -1;
-    }
-    return syscall(SC_set_thread_name, thread, buffer, buffer_size);
+    if (!name)
+        return EFAULT;
+    return syscall(SC_set_thread_name, thread, name, strlen(name));
 }
 
-int pthread_getname_np(pthread_t thread, char* buffer, int buffer_size)
+int pthread_getname_np(pthread_t thread, char* buffer, size_t buffer_size)
 {
-    if (buffer_size < 0) {
-        errno = EINVAL;
-        return -1;
-    }
     return syscall(SC_get_thread_name, thread, buffer, buffer_size);
 }
 
diff --git a/Libraries/LibPthread/pthread.h b/Libraries/LibPthread/pthread.h
index 64fa2a6da6..2f74515dcf 100644
--- a/Libraries/LibPthread/pthread.h
+++ b/Libraries/LibPthread/pthread.h
@@ -82,7 +82,7 @@ int pthread_mutexattr_init(pthread_mutexattr_t*);
 int pthread_mutexattr_settype(pthread_mutexattr_t*, int);
 int pthread_mutexattr_destroy(pthread_mutexattr_t*);
 
-int pthread_setname_np(pthread_t, const char*, int);
-int pthread_getname_np(pthread_t, char*, int);
+int pthread_setname_np(pthread_t, const char*);
+int pthread_getname_np(pthread_t, char*, size_t);
 
 __END_DECLS
diff --git a/Libraries/LibThread/Thread.cpp b/Libraries/LibThread/Thread.cpp
index ac97ce8d1b..b236ffe0ec 100644
--- a/Libraries/LibThread/Thread.cpp
+++ b/Libraries/LibThread/Thread.cpp
@@ -33,7 +33,7 @@ void LibThread::Thread::start()
 
     ASSERT(rc == 0);
     if (!m_thread_name.is_empty()) {
-        rc = pthread_setname_np(m_tid, m_thread_name.characters(), m_thread_name.length());
+        rc = pthread_setname_np(m_tid, m_thread_name.characters());
         ASSERT(rc == 0);
     }
     dbg() << "Started a thread, tid = " << m_tid;