From d12f292405270cf9c282911a41c40159379877c7 Mon Sep 17 00:00:00 2001
From: goodruyas <211121886+goodruyas@users.noreply.github.com>
Date: Wed, 9 Sep 2026 16:27:36 +0800
Subject: [PATCH] common : reject non-positive batch size (#28525)

---
 common/arg.cpp            | 3 +++
 src/llama-context.cpp     | 4 ++--
 tests/test-arg-parser.cpp | 7 +++++++
 3 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/common/arg.cpp b/common/arg.cpp
index 74241f931285..d555663c47ef 100644
--- a/common/arg.cpp
+++ b/common/arg.cpp
@@ -1677,6 +1677,9 @@ common_params_context common_params_parser_init(common_params & params, llama_ex
         {"-b", "--batch-size"}, "N",
         string_format("logical maximum batch size (default: %d)", params.n_batch),
         [](common_params & params, int value) {
+            if (value <= 0) {
+                throw std::invalid_argument("value must be positive");
+            }
             params.n_batch = value;
         }
     ).set_env("LLAMA_ARG_BATCH"));
diff --git a/src/llama-context.cpp b/src/llama-context.cpp
index 21501574a911..ee3e4bf0e135 100644
--- a/src/llama-context.cpp
+++ b/src/llama-context.cpp
@@ -3665,8 +3665,8 @@ llama_context * llama_init_from_model(
         return nullptr;
     }
 
-    if (params.n_batch == 0 && params.n_ubatch == 0) {
-        LLAMA_LOG_ERROR("%s: n_batch and n_ubatch cannot both be zero\n", __func__);
+    if (params.n_batch == 0) {
+        LLAMA_LOG_ERROR("%s: n_batch cannot be zero\n", __func__);
         return nullptr;
     }
 
diff --git a/tests/test-arg-parser.cpp b/tests/test-arg-parser.cpp
index e0907631abd8..10f63cd7ebbd 100644
--- a/tests/test-arg-parser.cpp
+++ b/tests/test-arg-parser.cpp
@@ -182,6 +182,13 @@ static void test(void) {
     argv = {"binary_name", "-ngl", "hello"};
     assert(false == common_params_parse(argv.size(), list_str_to_char(argv).data(), params, LLAMA_EXAMPLE_COMMON));
 
+    // batch-size must be positive
+    argv = {"binary_name", "--batch-size", "0"};
+    assert(false == common_params_parse(argv.size(), list_str_to_char(argv).data(), params, LLAMA_EXAMPLE_COMMON));
+
+    argv = {"binary_name", "--batch-size", "-1"};
+    assert(false == common_params_parse(argv.size(), list_str_to_char(argv).data(), params, LLAMA_EXAMPLE_COMMON));
+
     // wrong value (enum)
     argv = {"binary_name", "-sm", "hello"};
     assert(false == common_params_parse(argv.size(), list_str_to_char(argv).data(), params, LLAMA_EXAMPLE_COMMON));