diff --git a/ggml_extend.hpp b/ggml_extend.hpp
index 560d28613..b88344e18 100644
--- a/ggml_extend.hpp
+++ b/ggml_extend.hpp
@@ -56,6 +56,25 @@
 #define __STATIC_INLINE__ static inline
 #endif
 
+__STATIC_INLINE__ void ggml_log_callback_default(ggml_log_level level, const char* text, void*) {
+    switch (level) {
+        case GGML_LOG_LEVEL_DEBUG:
+            LOG_DEBUG(text);
+            break;
+        case GGML_LOG_LEVEL_INFO:
+            LOG_INFO(text);
+            break;
+        case GGML_LOG_LEVEL_WARN:
+            LOG_WARN(text);
+            break;
+        case GGML_LOG_LEVEL_ERROR:
+            LOG_ERROR(text);
+            break;
+        default:
+            LOG_DEBUG(text);
+    }
+}
+
 static_assert(GGML_MAX_NAME >= 128, "GGML_MAX_NAME must be at least 128");
 
 // n-mode trensor-matrix product
@@ -124,13 +143,6 @@ __STATIC_INLINE__ struct ggml_tensor* ggml_kronecker(ggml_context* ctx, struct g
                     b);
 }
 
-__STATIC_INLINE__ void ggml_log_callback_default(ggml_log_level level, const char* text, void* user_data) {
-    (void)level;
-    (void)user_data;
-    fputs(text, stderr);
-    fflush(stderr);
-}
-
 __STATIC_INLINE__ void ggml_tensor_set_f32_randn(struct ggml_tensor* tensor, std::shared_ptr<RNG> rng) {
     uint32_t n                        = (uint32_t)ggml_nelements(tensor);
     std::vector<float> random_numbers = rng->randn(n);
diff --git a/stable-diffusion.cpp b/stable-diffusion.cpp
index 088947311..9c30fa2d4 100644
--- a/stable-diffusion.cpp
+++ b/stable-diffusion.cpp
@@ -145,7 +145,6 @@ class StableDiffusionGGML {
 #endif
 #ifdef SD_USE_METAL
         LOG_DEBUG("Using Metal backend");
-        ggml_log_set(ggml_log_callback_default, nullptr);
         backend = ggml_backend_metal_init();
 #endif
 #ifdef SD_USE_VULKAN
@@ -192,6 +191,8 @@ class StableDiffusionGGML {
             rng = std::make_shared<PhiloxRNG>();
         }
 
+        ggml_log_set(ggml_log_callback_default, nullptr);
+
         init_backend();
 
         ModelLoader model_loader;
diff --git a/upscaler.cpp b/upscaler.cpp
index 4ab0b73c2..2bd62c09e 100644
--- a/upscaler.cpp
+++ b/upscaler.cpp
@@ -19,13 +19,13 @@ struct UpscalerGGML {
 
     bool load_from_file(const std::string& esrgan_path,
                         bool offload_params_to_cpu) {
+        ggml_log_set(ggml_log_callback_default, nullptr);
 #ifdef SD_USE_CUDA
         LOG_DEBUG("Using CUDA backend");
         backend = ggml_backend_cuda_init(0);
 #endif
 #ifdef SD_USE_METAL
         LOG_DEBUG("Using Metal backend");
-        ggml_log_set(ggml_log_callback_default, nullptr);
         backend = ggml_backend_metal_init();
 #endif
 #ifdef SD_USE_VULKAN
diff --git a/util.cpp b/util.cpp
index c2468ac54..b9142e606 100644
--- a/util.cpp
+++ b/util.cpp
@@ -414,7 +414,10 @@ void log_printf(sd_log_level_t level, const char* file, int line, const char* fo
     if (written >= 0 && written < LOG_BUFFER_SIZE) {
         vsnprintf(log_buffer + written, LOG_BUFFER_SIZE - written, format, args);
     }
-    strncat(log_buffer, "\n", LOG_BUFFER_SIZE - strlen(log_buffer));
+    size_t len = strlen(log_buffer);
+    if (log_buffer[len - 1] != '\n') {
+        strncat(log_buffer, "\n", LOG_BUFFER_SIZE - len);
+    }
 
     if (sd_log_cb) {
         sd_log_cb(level, log_buffer, sd_log_cb_data);