diff --git a/src/backend/ftrace.c b/src/backend/ftrace.c
index 6147b93..3291eed 100644
--- a/src/backend/ftrace.c
+++ b/src/backend/ftrace.c
@@ -43,6 +43,10 @@ static void set_trace(const char* value, const char* path) {
 	char filename[FTRACE_MAX_PATH];
 	sprintf(filename, "%s/%s", TRACE_BASE, path);
 	FILE *file = fopen(filename, "w");
+	if (!file) {
+		log_error("Failed to open %s\n", filename);
+		return;
+	}
 	fprintf(file, "%s", value);
 	fclose(file);
 }
@@ -116,7 +120,7 @@ static struct Tracenode* __process_stacktrace() {
 	int callsite_len = 0;
 	callsite_arg = ftrace_line + strlen(FTRACE_STACK_TRACE_SIGN);
 	callsite_len = strlen(callsite_arg);
-	strcpy(callsite, callsite_arg);
+	strncpy(callsite, callsite_arg, MAX_SYMBOL);
 	callsite[callsite_len - 1] = '\0';
 
 	// Process next traceline
@@ -219,6 +223,7 @@ static void do_ftrace_process() {
 		last = pre_last;
 		pre_last = NULL;
 	}
+
 	if (strncmp(last + 2, FTRACE_STACK_TRACE_EVENT, strlen(FTRACE_STACK_TRACE_EVENT) - 1) == 0) {
 		if (!task) {
 			log_debug("Got unexpected stacktrace!\n");
@@ -240,6 +245,11 @@ static void do_ftrace_process() {
 		event_info = pre_last;
 		pid_arg = pre_last;
 
+		if (!task_info || !event_info || !pid_arg) {
+			log_warn("Invalid line:\n%s\n", ftrace_line);
+			return;
+		}
+
 		while(pid_arg[0] != '-') {
 			pid_arg --;
 			if (pid_arg <= ftrace_line) {
@@ -252,6 +262,9 @@ static void do_ftrace_process() {
 			pid_arg[0] = '\0';
 			pid_arg++;
 			sscanf(pid_arg, "%u", &pid);
+		} else {
+			log_warn("Invalid line:\n%s\n", ftrace_line);
+			return;
 		}
 
 		event_info[0] = '\0';
@@ -261,11 +274,6 @@ static void do_ftrace_process() {
 			task_info++;
 		}
 
-		if (!task_info || !event_info || !pid_arg) {
-			log_warn("Invalid line:\n%s\n", ftrace_line);
-			return;
-		}
-
 		// char *event, *callsite;
 		event = strtok(event_info, " ");
 		// callsite = strtok(NULL, " ");
diff --git a/src/backend/perf-events.c b/src/backend/perf-events.c
index 5dbb88f..482100b 100644
--- a/src/backend/perf-events.c
+++ b/src/backend/perf-events.c
@@ -378,7 +378,7 @@ static int perf_debug_handler(struct PerfEventRing *ring, const unsigned char* h
 
 static int perf_handle_lost_event(const unsigned char* header, int cpu, char *event_name) {
 	struct perf_lost_events *body = (struct perf_lost_events*)header;
-	log_warn("Lost %d %s events on CPU %d!\n", body->lost, event_name, cpu);
+	log_warn("Lost %lu %s events on CPU %d!\n", body->lost, event_name, cpu);
 	return 0;
 }
 
diff --git a/src/backend/perf-sys.c b/src/backend/perf-sys.c
index 0bc9f63..3d5b35d 100644
--- a/src/backend/perf-sys.c
+++ b/src/backend/perf-sys.c
@@ -137,7 +137,8 @@ int perf_do_load_event_info(struct PerfEvent *event)
 		}
 	} else {
 		log_error("Failed to verify event name of %s\n", event->name);
-		return 1;
+		ret = 1;
+		goto out;
 	}
 
 	fgets(fmt_buffer, 1024, fmt_file);
diff --git a/src/memstrack.c b/src/memstrack.c
index a0d392c..02b8d48 100644
--- a/src/memstrack.c
+++ b/src/memstrack.c
@@ -215,9 +215,7 @@ static void init_fds(void) {
 }
 
 static void loop(void) {
-	int ret;
-
-	switch (ret = poll(m_pollfds, m_pollfd_num, 250)) {
+	switch (poll(m_pollfds, m_pollfd_num, 250)) {
 		// Resizing the terminal causes poll() to return -1
 		case -1:
 		default:
diff --git a/src/proc.c b/src/proc.c
index 1106c05..79206b7 100644
--- a/src/proc.c
+++ b/src/proc.c
@@ -110,6 +110,7 @@ int print_slab_usage()
 		log_info("%17s: %.1lf MB\n", entry->name, size_in_mb);
 	}
 
+	fclose(file);
 	return 0;
 }
 
@@ -167,23 +168,23 @@ int parse_zone_info(struct zone_info **zone)
 		strncpy((*zone)->name, zone_name, ZONENAMELEN);
 
 		log_debug("Trying to parse node %d zone %s\n", node, zone_name, (*zone)->start_pfn, (*zone)->spanned);
-		if (parse_keyword(1, file, line, "free", "Node", "free %d", &(*zone)->free))
+		if (parse_keyword(1, file, line, "free", "Node", "free %lu", &(*zone)->free))
 			continue;
-		if (parse_keyword(0, file, line, "min", NULL, "min %d", &(*zone)->min))
+		if (parse_keyword(0, file, line, "min", NULL, "min %lu", &(*zone)->min))
 			continue;
-		if (parse_keyword(0, file, line, "low", NULL, "low %d", &(*zone)->low))
+		if (parse_keyword(0, file, line, "low", NULL, "low %lu", &(*zone)->low))
 			continue;
-		if (parse_keyword(0, file, line, "high", NULL, "low %d", &(*zone)->high))
+		if (parse_keyword(0, file, line, "high", NULL, "low %lu", &(*zone)->high))
 			continue;
-		if (parse_keyword(0, file, line, "spanned", NULL, "spanned %d", &(*zone)->spanned))
+		if (parse_keyword(0, file, line, "spanned", NULL, "spanned %lu", &(*zone)->spanned))
 			continue;
-		if (parse_keyword(0, file, line, "present", NULL, "present %d", &(*zone)->present))
+		if (parse_keyword(0, file, line, "present", NULL, "present %lu", &(*zone)->present))
 			continue;
-		if (parse_keyword(0, file, line, "managed", NULL, "managed %d", &(*zone)->managed))
+		if (parse_keyword(0, file, line, "managed", NULL, "managed %lu", &(*zone)->managed))
 			continue;
-		if (parse_keyword(1, file, line, "start_pfn", "Node", "start_pfn: %d", &(*zone)->start_pfn))
+		if (parse_keyword(1, file, line, "start_pfn", "Node", "start_pfn: %lu", &(*zone)->start_pfn))
 			continue;
-		log_debug("Page span is start: %d, spanned %d\n", node, zone_name, (*zone)->start_pfn, (*zone)->spanned);
+		log_debug("Page span is start: %lu, spanned %lu\n", (*zone)->start_pfn, (*zone)->spanned);
 
 		zone = &(*zone)->next_zone;
 	}
diff --git a/src/report.c b/src/report.c
index cebd002..5a60bb0 100644
--- a/src/report.c
+++ b/src/report.c
@@ -32,7 +32,7 @@ static void report_module_summary(void) {
 
 	for (int i = 0; i < module_map.size; ++i) {
 		log_info(
-				"Module %s using %.1lfMB (%d pages), peak allocation %.1lfMB (%d pages)\n",
+				"Module %s using %.1lfMB (%ld pages), peak allocation %.1lfMB (%ld pages)\n",
 				modules[i]->name,
 				modules[i]->tracenode.record->pages_alloc * ((double)page_size) / 1024 / 1024,
 				modules[i]->tracenode.record->pages_alloc,
@@ -66,7 +66,7 @@ static void report_task_summary (void) {
 	tasks = collect_tasks_sorted(0);
 	for (int i = 0; i < task_map.size; ++i) {
 		log_info(
-				"Task %s (%u) using %u pages, peak usage %u pages\n",
+				"Task %s (%ld) using %ld pages, peak usage %ld pages\n",
 				tasks[i]->task_name, tasks[i]->pid,
 				tasks[i]->tracenode.record->pages_alloc,
 				tasks[i]->tracenode.record->pages_alloc_peak);
diff --git a/src/tracing.c b/src/tracing.c
index d63acc4..b0dc448 100644
--- a/src/tracing.c
+++ b/src/tracing.c
@@ -117,6 +117,9 @@ static char* get_process_name_by_pid(const int pid)
 		size = fread(buf, sizeof(char), TASK_NAME_LEN_MAX, f);
 		if (size > 0){
 			buf[size - 1] = '\0';
+		} else {
+			// TODO: empty name?
+			buf[0] = '\0';
 		}
 		fclose(f);
 	} else {
@@ -294,6 +297,10 @@ static void record_page_free(unsigned long pfn, unsigned long nr_pages) {
 
 static void do_update_record(struct Tracenode *tracenode, struct PageEvent *pevent) {
 	if (pevent->pages_alloc > 0) {
+		if (!tracenode) {
+			log_debug("BUG: Page alloc event with NULL tracenode\n");
+			return;
+		}
 		record_page_alloc(tracenode, pevent->pfn, pevent->pages_alloc);
 	} else if (pevent->pages_alloc < 0) {
 		record_page_free(pevent->pfn, 0 - pevent->pages_alloc);
@@ -427,6 +434,11 @@ void load_kallsyms() {
 	FILE *proc_kallsyms = fopen("/proc/kallsyms", "r");
 	char read_buf[4096];
 
+	if (!proc_kallsyms) {
+		log_error("Failed to open /proc/kallsyms\n");
+		return;
+	}
+
 	while(fgets(read_buf, 4096, proc_kallsyms)) {
 		unsigned long long addr;
 		char *addr_arg = strtok(read_buf, " \t");
@@ -674,10 +686,15 @@ struct Tracenode **collect_tracenodes_sorted(struct Tracenode *root, int *count,
 	struct Tracenode **nodes, **tail;
 
 	*count = count_tracenodes(root);
-	tail = nodes = malloc(*count * sizeof(struct Tracenode*));
+	tail = nodes = calloc(*count * sizeof(struct Tracenode*), 1);
 	for_each_tracenode(root, tracenode_iter_collect, &tail);
 
 	for (int i = 0; i < *count; ++i) {
+		if (!nodes[i]) {
+			*count = i;
+			break;
+		}
+
 		if (shallow)
 			populate_tracenode_shallow(nodes[i]);
 		else
@@ -742,8 +759,8 @@ void print_tracenode_json(struct Tracenode* tracenode, void *blob) {
 	}
 	log_info("%s\"%s\": ", padding, get_tracenode_symbol(tracenode));
 	log_info("{\n");
-	log_info("%s \"pages_alloc\": %d", padding, tracenode->record->pages_alloc);
-	log_info(",\n%s \"pages_alloc_peak\": %d", padding, tracenode->record->pages_alloc_peak);
+	log_info("%s \"pages_alloc\": %ld", padding, tracenode->record->pages_alloc);
+	log_info(",\n%s \"pages_alloc_peak\": %ld", padding, tracenode->record->pages_alloc_peak);
 
 	if (tracenode->children) {
 		log_info(",\n%s \"tracenodes\": {\n", padding);
@@ -768,9 +785,9 @@ void print_task_json(struct Task* task) {
 
 	log_info(" {\n");
 	log_info("  \"task_name\": \"%s\",\n", task->task_name);
-	log_info("  \"pid\" :\"%d\",\n", task->pid);
-	log_info("  \"pages_alloc\": %d,\n", task->tracenode.record->pages_alloc);
-	log_info("  \"pages_alloc_peak\": %d,\n", task->tracenode.record->pages_alloc_peak);
+	log_info("  \"pid\" :\"%ld\",\n", task->pid);
+	log_info("  \"pages_alloc\": %ld,\n", task->tracenode.record->pages_alloc);
+	log_info("  \"pages_alloc_peak\": %ld,\n", task->tracenode.record->pages_alloc_peak);
 	log_info("  \"tracenodes\": {\n");
 	if(to_tracenode(task)->children) {
 		nodes = collect_tracenodes_sorted(to_tracenode(task)->children, &counter, 1);
@@ -792,18 +809,17 @@ void print_tracenode(struct Tracenode* tracenode, int current_indent, int substa
 
 	log_info("%s", get_tracenode_symbol(tracenode));
 
-	log_info(" Pages: %d (peak: %d)\n",
+	log_info(" Pages: %ld (peak: %ld)\n",
 			tracenode->record->pages_alloc,
 			tracenode->record->pages_alloc_peak);
 
 	if (m_sort_peak)
 		page_limit = tracenode->record->pages_alloc_peak;
-	else if (m_sort_alloc)
+	else
 		page_limit = tracenode->record->pages_alloc;
 
-	if (throttle) {
+	if (throttle)
 		page_limit = page_limit * throttle / 100;
-	}
 
 	if (tracenode->children) {
 		struct Tracenode **nodes;
@@ -827,7 +843,7 @@ void print_task(struct Task* task) {
 	struct Tracenode **nodes;
 
 	indent = 2;
-	log_info("%s Pages: %d (peak: %d)\n",
+	log_info("%s Pages: %ld (peak: %ld)\n",
 			task->task_name,
 			tn->record->pages_alloc,
 			tn->record->pages_alloc_peak);
diff --git a/src/tui.c b/src/tui.c
index 5ae2228..0afe66a 100644
--- a/src/tui.c
+++ b/src/tui.c
@@ -138,6 +138,7 @@ static void trace_refresh_tui() {
 
 	info = &line_info;
 
+	// TODO: only work when it's single thread
 	for (int task_n = 0; task_n < tasks_num; ++task_n) {
 		if (tui_print_tracenode(to_tracenode(sorted_tasks[task_n]), 0))
 			return;
@@ -272,6 +273,7 @@ void tui_init(void) {
 
 void tui_update(void) {
 	int ch;
+	int ret;
 
 	if (ui_fds[0].revents & POLLIN) {
 		/* On UI event */
@@ -306,7 +308,8 @@ void tui_update(void) {
 
 	if (ui_fds[1].revents & POLLIN) {
 		uint64_t time;
-		read(ui_fds[1].fd, &time, sizeof(time));
-		update_ui(trace_win);
+		ret = read(ui_fds[1].fd, &time, sizeof(time));
+		if (ret)
+			update_ui(trace_win);
 	}
 }
diff --git a/src/utils.c b/src/utils.c
index 118cc6d..d8a382a 100644
--- a/src/utils.c
+++ b/src/utils.c
@@ -165,8 +165,10 @@ void insert_tree_node(
 	struct TreeNode *root = *root_p;
 	int result;
 
-	if (root == NULL)
+	if (root == NULL) {
 		*root_p = src;
+		return;
+	}
 
 	while (1) {
 		result = comp(root, key);