From bfd322796cd838f906535ff3352624fc46338894 Mon Sep 17 00:00:00 2001
From: Xuan-Son Nguyen <son@huggingface.co>
Date: Mon, 2 Jun 2025 16:29:28 +0200
Subject: [PATCH] mtmd : fix memory leak in mtmd_helper_eval_chunk_single
 (#13961)

* mtmd : fix memory in mtmd_helper_eval_chunk_single

* mtmd-cli : fix mem leak

* Update tools/mtmd/mtmd-cli.cpp

Co-authored-by: Georgi Gerganov <ggerganov@gmail.com>

---------

Co-authored-by: Georgi Gerganov <ggerganov@gmail.com>
---
 tools/mtmd/mtmd-cli.cpp    | 20 +++++++++++++-------
 tools/mtmd/mtmd-helper.cpp |  1 +
 2 files changed, 14 insertions(+), 7 deletions(-)

diff --git a/tools/mtmd/mtmd-cli.cpp b/tools/mtmd/mtmd-cli.cpp
index 508a64c58..40deab5ab 100644
--- a/tools/mtmd/mtmd-cli.cpp
+++ b/tools/mtmd/mtmd-cli.cpp
@@ -70,6 +70,7 @@ struct mtmd_cli_context {
     llama_model       * model;
     llama_context     * lctx;
     const llama_vocab * vocab;
+    common_sampler    * smpl;
     llama_batch         batch;
     int                 n_batch;
 
@@ -89,8 +90,9 @@ struct mtmd_cli_context {
         model = llama_init.model.get();
         lctx = llama_init.context.get();
         vocab = llama_model_get_vocab(model);
+        smpl = common_sampler_init(model, params.sampling);
         n_threads = params.cpuparams.n_threads;
-        batch = llama_batch_init(params.n_batch, 0, 1);
+        batch = llama_batch_init(1, 0, 1); // batch for next token generation
         n_batch = params.n_batch;
 
         if (!model || !lctx) {
@@ -118,6 +120,11 @@ struct mtmd_cli_context {
         }
     }
 
+    ~mtmd_cli_context() {
+        llama_batch_free(batch);
+        common_sampler_free(smpl);
+    }
+
     void init_vision_context(common_params & params) {
         const char * clip_path = params.mmproj.path.c_str();
         mtmd_context_params mparams = mtmd_context_params_default();
@@ -153,7 +160,7 @@ struct mtmd_cli_context {
     }
 };
 
-static int generate_response(mtmd_cli_context & ctx, common_sampler * smpl, int n_predict) {
+static int generate_response(mtmd_cli_context & ctx, int n_predict) {
     llama_tokens generated_tokens;
     for (int i = 0; i < n_predict; i++) {
         if (i > n_predict || !g_is_generating || g_is_interrupted) {
@@ -161,9 +168,9 @@ static int generate_response(mtmd_cli_context & ctx, common_sampler * smpl, int
             break;
         }
 
-        llama_token token_id = common_sampler_sample(smpl, ctx.lctx, -1);
+        llama_token token_id = common_sampler_sample(ctx.smpl, ctx.lctx, -1);
         generated_tokens.push_back(token_id);
-        common_sampler_accept(smpl, token_id, true);
+        common_sampler_accept(ctx.smpl, token_id, true);
 
         if (llama_vocab_is_eog(ctx.vocab, token_id) || ctx.check_antiprompt(generated_tokens)) {
             LOG("\n");
@@ -261,7 +268,6 @@ int main(int argc, char ** argv) {
 
     bool is_single_turn = !params.prompt.empty() && !params.image.empty();
 
-    struct common_sampler * smpl = common_sampler_init(ctx.model, params.sampling);
     int n_predict = params.n_predict < 0 ? INT_MAX : params.n_predict;
 
     // Ctrl+C handling
@@ -300,7 +306,7 @@ int main(int argc, char ** argv) {
         if (eval_message(ctx, msg, true)) {
             return 1;
         }
-        if (!g_is_interrupted && generate_response(ctx, smpl, n_predict)) {
+        if (!g_is_interrupted && generate_response(ctx, n_predict)) {
             return 1;
         }
 
@@ -366,7 +372,7 @@ int main(int argc, char ** argv) {
                 return 1;
             }
             if (g_is_interrupted) break;
-            if (generate_response(ctx, smpl, n_predict)) {
+            if (generate_response(ctx, n_predict)) {
                 return 1;
             }
             content.clear();
diff --git a/tools/mtmd/mtmd-helper.cpp b/tools/mtmd/mtmd-helper.cpp
index 64f03fd1e..686f42f39 100644
--- a/tools/mtmd/mtmd-helper.cpp
+++ b/tools/mtmd/mtmd-helper.cpp
@@ -311,6 +311,7 @@ int32_t mtmd_helper_eval_chunk_single(mtmd_context * ctx,
         GGML_ABORT("chunk type not supported");
     }
 
+    llama_batch_free(text_batch);
     return 0;
 }