build: add --asan flag to build.sh, tcp_io: null sock/queues in destroy + guard read_cb/write_cb

build.sh

@@ -5,6 +5,7 @@
 #   -h, --help      Show this help
 #   --clean         Clean before build
 #   --full          Full rebuild (autoreconf + configure + make)
+#   --asan          Build with AddressSanitizer (debug)
 #   -j[N]           Build with N parallel jobs (default: 4)
 
 set -e  # Exit on error
@@ -21,6 +22,7 @@ fi
 # Parse arguments
 CLEAN=0
 FULL_REBUILD=0
+USE_ASAN=0
 JOBS="-j4"
 MAKE_ARGS=""
 
@@ -32,6 +34,7 @@ while [[ $# -gt 0 ]]; do
             echo "  -h, --help      Show this help"
             echo "  --clean         Clean before build"
             echo "  --full          Full rebuild (autoreconf + configure + make)"
+            echo "  --asan          Build with AddressSanitizer"
             echo "  -j[N]           Build with N parallel jobs (default: 4)"
             exit 0
             ;;
@@ -43,6 +46,10 @@ while [[ $# -gt 0 ]]; do
             FULL_REBUILD=1
             shift
             ;;
+        --asan)
+            USE_ASAN=1
+            shift
+            ;;
         -j*)
             JOBS="$1"
             shift
@@ -126,16 +133,29 @@ fi
 if [ ! -f Makefile ]; then
     echo ""
     echo "Running ./configure..."
-    ./configure
+    if [ "$USE_ASAN" -eq 1 ]; then
+        ./configure CFLAGS="-g -Og -fsanitize=address -fno-omit-frame-pointer -fno-pie" LDFLAGS="-no-pie"
+    else
+        ./configure
+    fi
 fi
 
 # Build (all .o files go to build/ directory, binary copied to project root)
 echo ""
 echo "Compiling with $JOBS..."
 BUILD_SUCCESS=0
-make $JOBS $MAKE_ARGS 2>&1 | tee build.log
+if [ "$USE_ASAN" -eq 1 ]; then
-if [ ${PIPESTATUS[0]} -eq 0 ]; then
+    echo "(AddressSanitizer enabled — lib/ and src/ only, skipping tests)"
+    AF="-fsanitize=address -fno-omit-frame-pointer -g -Og"
+    AL="-fsanitize=address"
+    (cd lib && make clean $JOBS $MAKE_ARGS 2>&1 && make "CFLAGS+=$AF" "LDFLAGS+=$AL" $JOBS $MAKE_ARGS 2>&1) || { echo "lib build failed"; exit 1; }
+    (cd src && make clean $JOBS $MAKE_ARGS 2>&1 && make "CFLAGS+=$AF" "LDFLAGS+=$AL" $JOBS $MAKE_ARGS 2>&1) || { echo "src build failed"; exit 1; }
     BUILD_SUCCESS=1
+else
+    make $JOBS $MAKE_ARGS 2>&1 | tee build.log
+    if [ ${PIPESTATUS[0]} -eq 0 ]; then
+        BUILD_SUCCESS=1
+    fi
 fi
 
 if [ $BUILD_SUCCESS -eq 1 ]; then

lib/tcp_io.c

@@ -127,11 +127,11 @@ void tcp_conn_destroy(struct tcp_conn* tc) {
         if (e->dgram && e->dgram != &tcp_fin_sentinel) memory_pool_free(tc->data_pool, e->dgram);
         queue_entry_free(e); queue_resume_callback(tc->write_queue);
     }
-    queue_free(tc->read_queue);
+    queue_free(tc->read_queue);  tc->read_queue = NULL;
-    queue_free(tc->write_queue);
+    queue_free(tc->write_queue); tc->write_queue = NULL;
 
     if (tc->write_buf) memory_pool_free(tc->data_pool, tc->write_buf);
-    if (tc->sock != SOCKET_INVALID) socket_close_wrapper(tc->sock);
+    if (tc->sock != SOCKET_INVALID) { socket_close_wrapper(tc->sock); tc->sock = SOCKET_INVALID; }
     memory_pool_destroy(tc->entry_pool);
     memory_pool_destroy(tc->data_pool);
     u_free(tc);
@@ -185,7 +185,7 @@ static void tcp_conn_handle_error(struct tcp_conn* tc, int err)
 static void read_cb(socket_t sock, void* arg) {
     (void)sock;
     struct tcp_conn* tc = (struct tcp_conn*)arg;
-    if (!tc || tc->sock == SOCKET_INVALID) return;
+    if (!tc || tc->sock == SOCKET_INVALID || !tc->read_queue) return;
 
     struct ll_entry* e = queue_entry_new_from_pool(tc->entry_pool);
     uint8_t* buf = memory_pool_alloc(tc->data_pool);
@@ -368,7 +368,7 @@ static void write_queue_fetch_cb(struct ll_queue* q, void* arg) {
 static void write_cb(socket_t sock, void* arg) {
     (void)sock;
     struct tcp_conn* tc = (struct tcp_conn*)arg;
-    if (!tc || tc->sock == SOCKET_INVALID) return;
+    if (!tc || tc->sock == SOCKET_INVALID || !tc->write_queue) return;
 
     if (!tc->connected) {
         int err = 0;