diff --git a/repos/base/include/base/allocator.h b/repos/base/include/base/allocator.h
index 17729af42f..8e30fae253 100644
--- a/repos/base/include/base/allocator.h
+++ b/repos/base/include/base/allocator.h
@@ -163,7 +163,7 @@ struct Genode::Range_allocator : Allocator
 	 * \param align     alignment of new block specified
 	 *                  as the power of two
 	 */
-	virtual Alloc_return alloc_aligned(size_t size, void **out_addr, int align = 0, addr_t from=0, addr_t to = ~0UL) = 0;
+	virtual Alloc_return alloc_aligned(size_t size, void **out_addr, int align, addr_t from=0, addr_t to = ~0UL) = 0;
 
 	/**
 	 * Allocate block at address
diff --git a/repos/base/include/base/allocator_avl.h b/repos/base/include/base/allocator_avl.h
index 2b7fab37de..376b90f18f 100644
--- a/repos/base/include/base/allocator_avl.h
+++ b/repos/base/include/base/allocator_avl.h
@@ -131,7 +131,7 @@ class Genode::Allocator_avl_base : public Range_allocator
 				/**
 				 * Find best-fitting block
 				 */
-				Block *find_best_fit(size_t size, unsigned align = 1,
+				Block *find_best_fit(size_t size, unsigned align,
 				                     addr_t from = 0UL, addr_t to = ~0UL);
 
 				/**
@@ -260,7 +260,7 @@ class Genode::Allocator_avl_base : public Range_allocator
 
 		int          add_range(addr_t base, size_t size) override;
 		int          remove_range(addr_t base, size_t size) override;
-		Alloc_return alloc_aligned(size_t size, void **out_addr, int align = 0,
+		Alloc_return alloc_aligned(size_t size, void **out_addr, int align,
 		                           addr_t from = 0, addr_t to = ~0UL) override;
 		Alloc_return alloc_addr(size_t size, addr_t addr) override;
 		void         free(void *addr) override;
@@ -272,8 +272,11 @@ class Genode::Allocator_avl_base : public Range_allocator
 		 ** Allocator interface **
 		 *************************/
 
-		bool alloc(size_t size, void **out_addr) override {
-			return (Allocator_avl_base::alloc_aligned(size, out_addr).is_ok()); }
+		bool alloc(size_t size, void **out_addr) override
+		{
+			return (Allocator_avl_base::alloc_aligned(
+				size, out_addr, log2(sizeof(addr_t))).is_ok());
+		}
 
 		void free(void *addr, size_t) override { free(addr); }
 
diff --git a/repos/base/src/core/include/core_mem_alloc.h b/repos/base/src/core/include/core_mem_alloc.h
index ceedc335aa..25d5eda827 100644
--- a/repos/base/src/core/include/core_mem_alloc.h
+++ b/repos/base/src/core/include/core_mem_alloc.h
@@ -159,7 +159,7 @@ class Genode::Mapped_mem_allocator : public Genode::Core_mem_translator
 		int add_range(addr_t base, size_t size) override { return -1; }
 		int remove_range(addr_t base, size_t size) override { return -1; }
 		Alloc_return alloc_aligned(size_t size, void **out_addr,
-		                           int align = 0, addr_t from = 0,
+		                           int align, addr_t from = 0,
 		                           addr_t to = ~0UL) override;
 		Alloc_return alloc_addr(size_t size, addr_t addr) override {
 			return Alloc_return::RANGE_CONFLICT; }
@@ -174,7 +174,7 @@ class Genode::Mapped_mem_allocator : public Genode::Core_mem_translator
 		 *************************/
 
 		bool   alloc(size_t size, void **out_addr) override {
-			return alloc_aligned(size, out_addr).is_ok(); }
+			return alloc_aligned(size, out_addr, log2(sizeof(addr_t))).is_ok(); }
 		void   free(void *addr, size_t) override;
 		size_t consumed() const override { return _phys_alloc->consumed(); }
 		size_t overhead(size_t size) const override {
@@ -277,7 +277,7 @@ class Genode::Core_mem_allocator : public Genode::Core_mem_translator
 		Alloc_return alloc_addr(size_t size, addr_t addr) override {
 			return Alloc_return::RANGE_CONFLICT; }
 
-		Alloc_return alloc_aligned(size_t size, void **out_addr, int align = 0,
+		Alloc_return alloc_aligned(size_t size, void **out_addr, int align,
 		                           addr_t from = 0, addr_t to = ~0UL) override
 		{
 			Lock::Guard lock_guard(_lock);
@@ -300,7 +300,7 @@ class Genode::Core_mem_allocator : public Genode::Core_mem_translator
 		 *************************/
 
 		bool alloc(size_t size, void **out_addr) override {
-			return alloc_aligned(size, out_addr).is_ok(); }
+			return alloc_aligned(size, out_addr, log2(sizeof(addr_t))).is_ok(); }
 
 		void free(void *addr, size_t size) override
 		{
diff --git a/repos/base/src/core/include/synced_range_allocator.h b/repos/base/src/core/include/synced_range_allocator.h
index df84c3cd81..c3ec4b978c 100644
--- a/repos/base/src/core/include/synced_range_allocator.h
+++ b/repos/base/src/core/include/synced_range_allocator.h
@@ -91,7 +91,7 @@ class Genode::Synced_range_allocator : public Range_allocator
 		int remove_range(addr_t base, size_t size) override {
 			return _synced_object()->remove_range(base, size); }
 
-		Alloc_return alloc_aligned(size_t size, void **out_addr, int align = 0,
+		Alloc_return alloc_aligned(size_t size, void **out_addr, int align,
 		                           addr_t from = 0, addr_t to = ~0UL) override {
 			return _synced_object()->alloc_aligned(size, out_addr, align, from, to); }