Index: kernel/generic/src/lib/memfnc.c
===================================================================
--- kernel/generic/src/lib/memfnc.c	(revision 931afbc21fb7256372512b67f529ef39acfc8ac8)
+++ kernel/generic/src/lib/memfnc.c	(revision 8338a81e441a841d8987874fd886687c76a0c0b0)
@@ -87,4 +87,31 @@
 }
 
+/** Compare two memory areas.
+ *
+ * @param s1  Pointer to the first area to compare.
+ * @param s2  Pointer to the second area to compare.
+ * @param len Size of the areas in bytes.
+ *
+ * @return Zero if areas have the same contents. If they differ,
+ *	   the sign of the result is the same as the sign of the
+ *	   difference of the first pair of different bytes.
+ *
+ */
+int memcmp(const void *s1, const void *s2, size_t len)
+{
+	uint8_t *u1 = (uint8_t *) s1;
+	uint8_t *u2 = (uint8_t *) s2;
+	size_t i;
+
+	for (i = 0; i < len; i++) {
+		if (*u1 != *u2)
+			return (int)(*u1) - (int)(*u2);
+		++u1;
+		++u2;
+	}
+
+	return 0;
+}
+
 /** @}
  */
Index: kernel/generic/src/lib/ubsan.c
===================================================================
--- kernel/generic/src/lib/ubsan.c	(revision 8338a81e441a841d8987874fd886687c76a0c0b0)
+++ kernel/generic/src/lib/ubsan.c	(revision 8338a81e441a841d8987874fd886687c76a0c0b0)
@@ -0,0 +1,219 @@
+// SPDX-License-Identifier: BSD-2-Clause
+/*
+ * Copyright (c) 2016, Linaro Limited
+ */
+
+/* Modified for HelenOS use by Jiří Zárevúcky. */
+
+#include <stdbool.h>
+#include <stdint.h>
+#include <stddef.h>
+#include <panic.h>
+#include <mem.h>
+
+#define PRINTF(...) printf(__VA_ARGS__)
+#define ubsan_panic() panic("... aborting ...")
+
+struct source_location {
+	const char *file_name;
+	uint32_t line;
+	uint32_t column;
+};
+
+struct type_descriptor {
+	uint16_t type_kind;
+	uint16_t type_info;
+	char type_name[];
+};
+
+struct type_mismatch_data {
+	struct source_location loc;
+	struct type_descriptor *type;
+	unsigned long alignment;
+	unsigned char type_check_kind;
+};
+
+struct overflow_data {
+	struct source_location loc;
+	struct type_descriptor *type;
+};
+
+struct shift_out_of_bounds_data {
+	struct source_location loc;
+	struct type_descriptor *lhs_type;
+	struct type_descriptor *rhs_type;
+};
+
+struct out_of_bounds_data {
+	struct source_location loc;
+	struct type_descriptor *array_type;
+	struct type_descriptor *index_type;
+};
+
+struct unreachable_data {
+	struct source_location loc;
+};
+
+struct vla_bound_data {
+	struct source_location loc;
+	struct type_descriptor *type;
+};
+
+struct invalid_value_data {
+	struct source_location loc;
+	struct type_descriptor *type;
+};
+
+struct nonnull_arg_data {
+	struct source_location loc;
+};
+
+struct nonnull_return_data {
+	struct source_location loc;
+	struct source_location attr_loc;
+};
+
+/*
+ * When compiling with -fsanitize=undefined the compiler expects functions
+ * with the following signatures. The functions are never called directly,
+ * only when undefined behavior is detected in instrumented code.
+ */
+void __ubsan_handle_type_mismatch(struct type_mismatch_data *data, unsigned long ptr);
+void __ubsan_handle_add_overflow(struct overflow_data *data, unsigned long lhs, unsigned long rhs);
+void __ubsan_handle_sub_overflow(struct overflow_data *data, unsigned long lhs, unsigned long rhs);
+void __ubsan_handle_mul_overflow(struct overflow_data *data, unsigned long lhs, unsigned long rhs);
+void __ubsan_handle_negate_overflow(struct overflow_data *data, unsigned long old_val);
+void __ubsan_handle_divrem_overflow(struct overflow_data *data, unsigned long lhs, unsigned long rhs);
+void __ubsan_handle_shift_out_of_bounds(struct shift_out_of_bounds_data *data, unsigned long lhs, unsigned long rhs);
+void __ubsan_handle_out_of_bounds(struct out_of_bounds_data *data, unsigned long idx);
+void __ubsan_handle_unreachable(struct unreachable_data *data);
+void __ubsan_handle_missing_return(struct unreachable_data *data);
+void __ubsan_handle_vla_bound_not_positive(struct vla_bound_data *data, unsigned long bound);
+void __ubsan_handle_load_invalid_value(struct invalid_value_data *data, unsigned long val);
+#if __GCC_VERSION < 60000
+void __ubsan_handle_nonnull_arg(struct nonnull_arg_data *data, size_t arg_no);
+#else
+void __ubsan_handle_nonnull_arg(struct nonnull_arg_data *data);
+#endif
+void __ubsan_handle_nonnull_return(struct nonnull_return_data *data);
+
+static void print_loc(const char *func, struct source_location *loc)
+{
+	const char *f = func;
+	const char func_prefix[] = "__ubsan_handle";
+
+	if (!memcmp(f, func_prefix, sizeof(func_prefix) - 1))
+		f += sizeof(func_prefix);
+
+	PRINTF("Undefined behavior %s at %s:%" PRIu32 " col %" PRIu32 "\n",
+	    f, loc->file_name, loc->line, loc->column);
+}
+
+void __ubsan_handle_type_mismatch(struct type_mismatch_data *data,
+    unsigned long ptr)
+{
+	print_loc(__func__, &data->loc);
+	ubsan_panic();
+}
+
+void __ubsan_handle_add_overflow(struct overflow_data *data,
+    unsigned long lhs,
+    unsigned long rhs)
+{
+	print_loc(__func__, &data->loc);
+	ubsan_panic();
+}
+
+void __ubsan_handle_sub_overflow(struct overflow_data *data,
+    unsigned long lhs,
+    unsigned long rhs)
+{
+	print_loc(__func__, &data->loc);
+	ubsan_panic();
+}
+
+void __ubsan_handle_mul_overflow(struct overflow_data *data,
+    unsigned long lhs,
+    unsigned long rhs)
+{
+	print_loc(__func__, &data->loc);
+	ubsan_panic();
+}
+
+void __ubsan_handle_negate_overflow(struct overflow_data *data,
+    unsigned long old_val)
+{
+	print_loc(__func__, &data->loc);
+	ubsan_panic();
+}
+
+void __ubsan_handle_divrem_overflow(struct overflow_data *data,
+    unsigned long lhs,
+    unsigned long rhs)
+{
+	print_loc(__func__, &data->loc);
+	ubsan_panic();
+}
+
+void __ubsan_handle_shift_out_of_bounds(struct shift_out_of_bounds_data *data,
+    unsigned long lhs,
+    unsigned long rhs)
+{
+	print_loc(__func__, &data->loc);
+	PRINTF("LHS type: %s, value: %lu, RHS type: %s, value: %lu\n",
+	    data->lhs_type->type_name, lhs, data->rhs_type->type_name, rhs);
+	ubsan_panic();
+}
+
+void __ubsan_handle_out_of_bounds(struct out_of_bounds_data *data,
+    unsigned long idx)
+{
+	print_loc(__func__, &data->loc);
+	ubsan_panic();
+}
+
+void __ubsan_handle_unreachable(struct unreachable_data *data)
+{
+	print_loc(__func__, &data->loc);
+	ubsan_panic();
+}
+
+void __ubsan_handle_missing_return(struct unreachable_data *data)
+{
+	print_loc(__func__, &data->loc);
+	ubsan_panic();
+}
+
+void __ubsan_handle_vla_bound_not_positive(struct vla_bound_data *data,
+    unsigned long bound)
+{
+	print_loc(__func__, &data->loc);
+	ubsan_panic();
+}
+
+void __ubsan_handle_load_invalid_value(struct invalid_value_data *data,
+    unsigned long val)
+{
+	print_loc(__func__, &data->loc);
+	ubsan_panic();
+}
+
+#if __GCC_VERSION < 60000
+void __ubsan_handle_nonnull_arg(struct nonnull_arg_data *data, size_t arg_no)
+{
+	print_loc(__func__, &data->loc);
+	ubsan_panic();
+}
+#else
+void __ubsan_handle_nonnull_arg(struct nonnull_arg_data *data)
+{
+	print_loc(__func__, &data->loc);
+	ubsan_panic();
+}
+#endif
+
+void __ubsan_handle_nonnull_return(struct nonnull_return_data *data)
+{
+	print_loc(__func__, &data->loc);
+	ubsan_panic();
+}