diff --git a/extensions/compat_xtables.c b/extensions/compat_xtables.c
index dbf5c11..7244d90 100644
--- a/extensions/compat_xtables.c
+++ b/extensions/compat_xtables.c
@@ -85,6 +85,20 @@ static bool xtnu_match_check(const char *table, const void *entry,
 }
 #endif
 
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 28) && \
+    LINUX_VERSION_CODE <  KERNEL_VERSION(2, 6, 34)
+static bool xtnu_match_check(const struct xt_mtchk_param *par)
+{
+	struct xtnu_match *nm = xtcompat_numatch(cm);
+
+	if (nm == NULL)
+		return false;
+	if (nm->checkentry == NULL)
+		return true;
+	return nm->checkentry(par);
+}
+#endif
+
 #if LINUX_VERSION_CODE <= KERNEL_VERSION(2, 6, 18)
 static void xtnu_match_destroy(const struct xt_match *cm, void *matchinfo,
     unsigned int matchinfosize)
@@ -105,7 +119,7 @@ static void xtnu_match_destroy(const struct xt_match *cm, void *matchinfo)
 }
 #endif
 
-#if LINUX_VERSION_CODE <= KERNEL_VERSION(2, 6, 27)
+#if LINUX_VERSION_CODE <= KERNEL_VERSION(2, 6, 34)
 int xtnu_register_match(struct xtnu_match *nt)
 {
 	struct xt_match *ct;
diff --git a/extensions/compat_xtables.h b/extensions/compat_xtables.h
index 343fca6..92748a8 100644
--- a/extensions/compat_xtables.h
+++ b/extensions/compat_xtables.h
@@ -60,7 +60,7 @@
 #	define init_net__proc_net     init_net.proc_net
 #endif
 
-#if LINUX_VERSION_CODE <= KERNEL_VERSION(2, 6, 27)
+#if LINUX_VERSION_CODE <= KERNEL_VERSION(2, 6, 34)
 #	define xt_match              xtnu_match
 #	define xt_register_match     xtnu_register_match
 #	define xt_unregister_match   xtnu_unregister_match
diff --git a/extensions/ipset/ipt_set.c b/extensions/ipset/ipt_set.c
index c8af290..ec1a40f 100644
--- a/extensions/ipset/ipt_set.c
+++ b/extensions/ipset/ipt_set.c
@@ -47,7 +47,7 @@ match(const struct sk_buff *skb, const struct xt_match_param *par)
 			 info->match_set.flags[0] & IPSET_MATCH_INV);
 }
 
-static bool
+static int
 checkentry(const struct xt_mtchk_param *par)
 {
 	struct ipt_set_info_match *info = par->matchinfo;
@@ -56,7 +56,7 @@ checkentry(const struct xt_mtchk_param *par)
 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,17)
 	if (matchsize != IPT_ALIGN(sizeof(struct ipt_set_info_match))) {
 		ip_set_printk("invalid matchsize %d", matchsize);
-		return 0;
+		return -EINVAL;
 	}
 #endif
 
@@ -65,14 +65,14 @@ checkentry(const struct xt_mtchk_param *par)
 	if (index == IP_SET_INVALID_ID) {
 		ip_set_printk("Cannot find set indentified by id %u to match",
 			      info->match_set.index);
-		return 0;	/* error */
+		return -ENOENT;
 	}
 	if (info->match_set.flags[IP_SET_MAX_BINDINGS] != 0) {
 		ip_set_printk("That's nasty!");
-		return 0;	/* error */
+		return -EINVAL;
 	}
 
-	return 1;
+	return 0;
 }
 
 static void destroy(const struct xt_mtdtor_param *par)
diff --git a/extensions/pknock/xt_pknock.c b/extensions/pknock/xt_pknock.c
index 842654e..a700041 100644
--- a/extensions/pknock/xt_pknock.c
+++ b/extensions/pknock/xt_pknock.c
@@ -1064,9 +1064,9 @@ out:
 	return ret;
 }
 
-#define RETURN_ERR(err) do { printk(KERN_ERR PKNOCK err); return false; } while (false)
+#define RETURN_ERR(err) do { printk(KERN_ERR PKNOCK err); return -EINVAL; } while (false)
 
-static bool pknock_mt_check(const struct xt_mtchk_param *par)
+static int pknock_mt_check(const struct xt_mtchk_param *par)
 {
 	struct xt_pknock_mtinfo *info = par->matchinfo;
 
@@ -1124,9 +1124,10 @@ static bool pknock_mt_check(const struct xt_mtchk_param *par)
 	}
 
 	if (!add_rule(info))
+		/* should ENOMEM here */
 		RETURN_ERR("add_rule() error in checkentry() function.\n");
 
-	return true;
+	return 0;
 }
 
 static void pknock_mt_destroy(const struct xt_mtdtor_param *par)
diff --git a/extensions/xt_condition.c b/extensions/xt_condition.c
index 3aed62c..f5fb98d 100644
--- a/extensions/xt_condition.c
+++ b/extensions/xt_condition.c
@@ -109,7 +109,7 @@ condition_mt(const struct sk_buff *skb, const struct xt_match_param *par)
 	return x ^ info->invert;
 }
 
-static bool condition_mt_check(const struct xt_mtchk_param *par)
+static int condition_mt_check(const struct xt_mtchk_param *par)
 {
 	struct xt_condition_mtinfo *info = par->matchinfo;
 	struct condition_variable *var;
@@ -121,21 +121,21 @@ static bool condition_mt_check(const struct xt_mtchk_param *par)
 		printk(KERN_INFO KBUILD_MODNAME ": name not allowed or too "
 		       "long: \"%.*s\"\n", (unsigned int)sizeof(info->name),
 		       info->name);
-		return false;
+		return -EINVAL;
 	}
 	/*
 	 * Let's acquire the lock, check for the condition and add it
 	 * or increase the reference counter.
 	 */
 	if (mutex_lock_interruptible(&proc_lock) != 0)
-		return false;
+		return -EINTR;
 
 	list_for_each_entry(var, &conditions_list, list) {
 		if (strcmp(info->name, var->status_proc->name) == 0) {
 			var->refcount++;
 			mutex_unlock(&proc_lock);
 			info->condvar = var;
-			return true;
+			return 0;
 		}
 	}
 
@@ -143,7 +143,7 @@ static bool condition_mt_check(const struct xt_mtchk_param *par)
 	var = kmalloc(sizeof(struct condition_variable), GFP_KERNEL);
 	if (var == NULL) {
 		mutex_unlock(&proc_lock);
-		return false;
+		return -ENOMEM;
 	}
 
 	/* Create the condition variable's proc file entry. */
@@ -152,7 +152,7 @@ static bool condition_mt_check(const struct xt_mtchk_param *par)
 	if (var->status_proc == NULL) {
 		kfree(var);
 		mutex_unlock(&proc_lock);
-		return false;
+		return -ENOMEM;
 	}
 
 	var->refcount = 1;
@@ -169,7 +169,7 @@ static bool condition_mt_check(const struct xt_mtchk_param *par)
 	var->status_proc->gid = condition_gid_perms;
 	mutex_unlock(&proc_lock);
 	info->condvar = var;
-	return true;
+	return 0;
 }
 
 static void condition_mt_destroy(const struct xt_mtdtor_param *par)
diff --git a/extensions/xt_fuzzy.c b/extensions/xt_fuzzy.c
index 0775cf2..83903b2 100644
--- a/extensions/xt_fuzzy.c
+++ b/extensions/xt_fuzzy.c
@@ -125,7 +125,7 @@ fuzzy_mt(const struct sk_buff *skb, const struct xt_match_param *par)
 	return false;
 }
 
-static bool fuzzy_mt_check(const struct xt_mtchk_param *par)
+static int fuzzy_mt_check(const struct xt_mtchk_param *par)
 {
 	const struct xt_fuzzy_mtinfo *info = par->matchinfo;
 
@@ -133,10 +133,10 @@ static bool fuzzy_mt_check(const struct xt_mtchk_param *par)
 	    info->maximum_rate > FUZZY_MAX_RATE ||
 	    info->minimum_rate >= info->maximum_rate) {
 		printk(KERN_INFO KBUILD_MODNAME ": bad values, please check.\n");
-		return false;
+		return -EDOM;
 	}
 
-	return true;
+	return 0;
 }
 
 static struct xt_match fuzzy_mt_reg[] __read_mostly = {
diff --git a/extensions/xt_geoip.c b/extensions/xt_geoip.c
index 8b9420d..76c643c 100644
--- a/extensions/xt_geoip.c
+++ b/extensions/xt_geoip.c
@@ -46,23 +46,28 @@ geoip_add_node(const struct geoip_country_user __user *umem_ptr)
 	struct geoip_country_user umem;
 	struct geoip_country_kernel *p;
 	struct geoip_subnet *s;
+	int ret;
 
 	if (copy_from_user(&umem, umem_ptr, sizeof(umem)) != 0)
-		return NULL;
+		return ERR_PTR(-EFAULT);
 
 	p = kmalloc(sizeof(struct geoip_country_kernel), GFP_KERNEL);
 	if (p == NULL)
-		return NULL;
+		return ERR_PTR(-ENOMEM);
 
 	p->count   = umem.count;
 	p->cc      = umem.cc;
 
 	s = vmalloc(p->count * sizeof(struct geoip_subnet));
-	if (s == NULL)
+	if (s == NULL) {
+		ret = -ENOMEM;
 		goto free_p;
+	}
 	if (copy_from_user(s, (const void __user *)(unsigned long)umem.subnets,
-	    p->count * sizeof(struct geoip_subnet)) != 0)
+	    p->count * sizeof(struct geoip_subnet)) != 0) {
+		ret = -EFAULT;
 		goto free_s;
+	}
 
 	p->subnets = s;
 	atomic_set(&p->ref, 1);
@@ -78,7 +83,7 @@ geoip_add_node(const struct geoip_country_user __user *umem_ptr)
 	vfree(s);
  free_p:
 	kfree(p);
-	return NULL;
+	return ERR_PTR(ret);
 }
 
 static void geoip_try_remove_node(struct geoip_country_kernel *p)
@@ -168,7 +173,7 @@ xt_geoip_mt(const struct sk_buff *skb, const struct xt_match_param *par)
 	return info->flags & XT_GEOIP_INV;
 }
 
-static bool xt_geoip_mt_checkentry(const struct xt_mtchk_param *par)
+static int xt_geoip_mt_checkentry(const struct xt_mtchk_param *par)
 {
 	struct xt_geoip_match_info *info = par->matchinfo;
 	struct geoip_country_kernel *node;
@@ -176,13 +181,15 @@ static bool xt_geoip_mt_checkentry(const struct xt_mtchk_param *par)
 
 	for (i = 0; i < info->count; i++) {
 		node = find_node(info->cc[i]);
-		if (node == NULL)
-			if ((node = geoip_add_node((const void __user *)(unsigned long)info->mem[i].user)) == NULL) {
+		if (node == NULL) {
+			node = geoip_add_node((const void __user *)(unsigned long)info->mem[i].user);
+			if (IS_ERR(node)) {
 				printk(KERN_ERR
-						"xt_geoip: unable to load '%c%c' into memory\n",
-						COUNTRY(info->cc[i]));
-				return false;
+						"xt_geoip: unable to load '%c%c' into memory: %ld\n",
+						COUNTRY(info->cc[i]), PTR_ERR(node));
+				return PTR_ERR(node);
 			}
+		}
 
 		/* Overwrite the now-useless pointer info->mem[i] with
 		 * a pointer to the node's kernelspace structure.
@@ -192,7 +199,7 @@ static bool xt_geoip_mt_checkentry(const struct xt_mtchk_param *par)
 		info->mem[i].kernel = node;
 	}
 
-	return true;
+	return 0;
 }
 
 static void xt_geoip_mt_destroy(const struct xt_mtdtor_param *par)
diff --git a/extensions/xt_lscan.c b/extensions/xt_lscan.c
index cf63a90..1f51f82 100644
--- a/extensions/xt_lscan.c
+++ b/extensions/xt_lscan.c
@@ -216,16 +216,16 @@ lscan_mt(const struct sk_buff *skb, const struct xt_match_param *par)
 	       (info->match_gr && ctdata->mark == mark_grscan);
 }
 
-static bool lscan_mt_check(const struct xt_mtchk_param *par)
+static int lscan_mt_check(const struct xt_mtchk_param *par)
 {
 	const struct xt_lscan_mtinfo *info = par->matchinfo;
 
 	if ((info->match_stealth & ~1) || (info->match_syn & ~1) ||
 	    (info->match_cn & ~1) || (info->match_gr & ~1)) {
 		printk(KERN_WARNING PFX "Invalid flags\n");
-		return false;
+		return -EINVAL;
 	}
-	return true;
+	return 0;
 }
 
 static struct xt_match lscan_mt_reg[] __read_mostly = {
diff --git a/extensions/xt_quota2.c b/extensions/xt_quota2.c
index f530b8b..ab9cb08 100644
--- a/extensions/xt_quota2.c
+++ b/extensions/xt_quota2.c
@@ -144,28 +144,28 @@ q2_get_counter(const struct xt_quota_mtinfo2 *q)
 	return NULL;
 }
 
-static bool quota_mt2_check(const struct xt_mtchk_param *par)
+static int quota_mt2_check(const struct xt_mtchk_param *par)
 {
 	struct xt_quota_mtinfo2 *q = par->matchinfo;
 
 	if (q->flags & ~XT_QUOTA_MASK)
-		return false;
+		return -EINVAL;
 
 	q->name[sizeof(q->name)-1] = '\0';
 	if (*q->name == '.' || strchr(q->name, '/') != NULL) {
 		printk(KERN_ERR "xt_quota<%u>: illegal name\n",
 		       par->match->revision);
-		return false;
+		return -EINVAL;
 	}
 
 	q->master = q2_get_counter(q);
 	if (q->master == NULL) {
 		printk(KERN_ERR "xt_quota<%u>: memory alloc failure\n",
 		       par->match->revision);
-		return false;
+		return -ENOMEM;
 	}
 
-	return true;
+	return 0;
 }
 
 static void quota_mt2_destroy(const struct xt_mtdtor_param *par)