diff --git a/kernel-src/io/net/vionet.c b/kernel-src/io/net/vionet.c
index 9d10c277..400849e6 100644
--- a/kernel-src/io/net/vionet.c
+++ b/kernel-src/io/net/vionet.c
@@ -230,6 +230,8 @@ int vionet_newdevice(viodevice_t *viodevice) {
 	char name[10];
 	snprintf(name, 10, "vionet%d", netdev->id);
 
+	netdev->netdev.flags = NETDEV_FLAGS_UP | NETDEV_FLAGS_BROADCAST | NETDEV_FLAGS_RUNNING;
+
 	__assert(netdev_register((netdev_t *)netdev, name) == 0);
 
 	return 0;
diff --git a/kernel-src/mm/alloc.c b/kernel-src/mm/alloc.c
index e213c726..ccab32c2 100644
--- a/kernel-src/mm/alloc.c
+++ b/kernel-src/mm/alloc.c
@@ -4,28 +4,37 @@
 #include <string.h>
 #include <kernel/init.h>
 
-// each allocation has the following structure:
-// ptr: data capacity (allocsizes size)
-// ptr + sizeof(size_t): current size
-// ptr + sizeof(size_t) * 2: data
-// ptr + datasize: poison value
-
-#define USE_POISON 0
+#define DEBUG 1
 #define POISON_VALUE 0xdeadbeefbadc0ffel
 #define CACHE_COUNT 14
 
-#define CAPACITY_SIZE(cache) cache->size - sizeof(size_t) * 2 - USE_POISON * sizeof(size_t)
+#if DEBUG == 1
+typedef struct {
+	size_t capacity;
+	size_t current_size;
+	size_t debug_address;
+	uint8_t data[];
+} alloc_header_t;
+#else
+typedef struct {
+	size_t capacity;
+	size_t current_size;
+	uint8_t data[];
+} alloc_header_t;
+#endif
+
+#define CAPACITY_SIZE(cache) cache->size - sizeof(alloc_header_t) - DEBUG * sizeof(size_t);
 
 static size_t allocsizes[CACHE_COUNT] = {32, 64, 128, 256, 512, 1024, 2048, 4096, 8192, 16384, 32768, 65536, 131072, 262144};
 static scache_t *caches[CACHE_COUNT + 5];
 
 static void initarea(scache_t *cache, void *obj, size_t size) {
-	size_t *ptr = obj;
-	*ptr = CAPACITY_SIZE(cache);
-	*(ptr + 1) = size;
-	memset(ptr + 2, 0, *ptr);
-	#if USE_POISON == 1
-	*((size_t *)((uintptr_t)obj + cache->size - sizeof(size_t))) = POISON_VALUE;
+	alloc_header_t *hdr = obj;
+	hdr->capacity = CAPACITY_SIZE(cache);
+	hdr->current_size = size;
+	memset(hdr->data, 0, hdr->capacity);
+	#if DEBUG == 1
+	*((size_t *)((uintptr_t)obj + cache->size - 1 * sizeof(size_t))) = POISON_VALUE;
 	#endif
 }
 
@@ -33,61 +42,74 @@ static scache_t *getcachefromsize(size_t size) {
 	if (unlikely(size <= 1))
 		return caches[0];
 
+	if (unlikely(size > 262144))
+		return NULL;
+
 	size_t i = 64 - __builtin_clzll(size - 1);
 	return caches[i];
 }
 
 void *alloc(size_t size) {
 	scache_t *cache = getcachefromsize(size);
-	size_t *ret = slab_allocate(cache);
+	if (unlikely(cache == NULL))
+		return NULL;
+
+	alloc_header_t *ret = slab_allocate(cache);
 	if (unlikely(ret == NULL))
 		return NULL;
 
 	initarea(cache, ret, size);
-	#if USE_POISON == 1
-		__assert(*ret == CAPACITY_SIZE(cache));
+	#if DEBUG == 1
+		__assert(*(size_t *)((uintptr_t)ret + cache->size - sizeof(size_t)) == POISON_VALUE);
+		ret->debug_address = (size_t)__builtin_return_address(0);
 	#endif
-	return ret + 2;
+	return ret->data;
 }
 
 void free(void *ptr) {
-	slab_free(getcachefromsize(*((size_t *)ptr - 2)), (size_t *)ptr - 2);
+	alloc_header_t *header = container_of(ptr, alloc_header_t, data);
+	scache_t *cache = getcachefromsize(header->capacity);
+	#if DEBUG == 1
+		__assert(cache);
+		header->current_size = 0;
+		__assert(*(size_t *)((uintptr_t)header + cache->size - sizeof(size_t)) == POISON_VALUE);
+	#endif
+	slab_free(cache, header);
 }
 
 void *realloc(void *ptr, size_t size) {
-	size_t *start = ptr;
-	start -= 2;
-	size_t currentsize = *(start + 1);
-	if (size <= currentsize) {
-		*(start + 1) = size;
+	alloc_header_t *header = container_of(ptr, alloc_header_t, data);
+	if (size <= header->capacity) {
+		header->current_size = size;
 		return ptr;
 	}
 
 	// grow
-	scache_t *oldcache = getcachefromsize(*start);
-	scache_t *newcache = getcachefromsize(size);
+	scache_t *old_cache = getcachefromsize(header->capacity);
+	scache_t *new_cache = getcachefromsize(size);
 
 	// same allocation
-	if (oldcache == newcache) {
-		size_t diff = size - currentsize;
-		memset((void *)((uintptr_t)ptr + currentsize), 0, diff);
-		*(start + 1) = size;
+	if (old_cache == new_cache) {
+		size_t diff = size - header->current_size;
+		memset((void *)((uintptr_t)ptr + header->current_size), 0, diff);
+		header->current_size = size;
 		return ptr;
 	}
 
 	// different allocation
-	size_t *new = slab_allocate(newcache);
+	alloc_header_t *new = slab_allocate(new_cache);
 	if (new == NULL)
 		return NULL;
-	initarea(newcache, new, size);
-	memcpy((new + 2), ptr, currentsize);
-	slab_free(oldcache, start);
-	return new + 2;
+
+	initarea(new_cache, new, size);
+	memcpy(new->data, ptr, header->current_size);
+	slab_free(old_cache, header);
+	return new->data;
 }
 
 void alloc_init() {
 	for (int i = 0; i < CACHE_COUNT; ++i) {
-		caches[i + 5] = slab_newcache(allocsizes[i] + sizeof(size_t) * 2 + sizeof(size_t) * USE_POISON, 0, NULL, NULL);
+		caches[i + 5] = slab_newcache(allocsizes[i] + sizeof(alloc_header_t) + sizeof(size_t) * DEBUG, 0, NULL, NULL);
 		__assert(caches[i + 5]);
 		void *p = slab_allocate(caches[i + 5]);
 		__assert(p);