From 6951801bbc8f51be5db0b9262ac5e5349bf7d9d5 Mon Sep 17 00:00:00 2001
From: Loic Coenen <loic@visua.com>
Date: Sun, 3 May 2026 19:27:00 +0000
Subject: [PATCH] fix: replace real-time unsafe malloc with stack buffers in
 process_callback

Co-authored-by: aider (deepseek/deepseek-coder) <aider@aider.chat>
---
 engine.c | 16 +++++++---------
 1 file changed, 7 insertions(+), 9 deletions(-)

diff --git a/engine.c b/engine.c
index 0eac350..aa0af00 100644
--- a/engine.c
+++ b/engine.c
@@ -1,5 +1,7 @@
 #include "engine.h"
 #include "carla.h"
+
+#define MAX_NFRAMES 8192
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -125,13 +127,11 @@ static int process_callback(jack_nframes_t nframes, void *arg) {
     for (int ch = 0; ch < MAX_CHANNELS; ch++) {
         memset(audio_out[ch], 0, sizeof(jack_default_audio_sample_t) * nframes);
         
-        // Create temporary buffer for rack processing
-        float *rack_in = malloc(nframes * sizeof(float));
-        float *rack_out = malloc(nframes * sizeof(float));
-        
-        if (!rack_in || !rack_out) {
-            free(rack_in);
-            free(rack_out);
+        // Use stack-allocated buffers (max MAX_NFRAMES samples)
+        float rack_in[MAX_NFRAMES];
+        float rack_out[MAX_NFRAMES];
+        if (nframes > MAX_NFRAMES) {
+            // Should never happen with JACK, but guard
             continue;
         }
         
@@ -164,8 +164,6 @@ static int process_callback(jack_nframes_t nframes, void *arg) {
         // Copy to output
         memcpy(audio_out[ch], rack_out, nframes * sizeof(jack_default_audio_sample_t));
         
-        free(rack_in);
-        free(rack_out);
     }
     
     return 0;