From 58f32cd6909aa83c107175ecf1e03c1148b7bc26 Mon Sep 17 00:00:00 2001
From: Feoramund <161657516+Feoramund@users.noreply.github.com>
Date: Tue, 22 Jul 2025 10:40:16 -0400
Subject: [PATCH 1/2] Fix Linux-specific optimized test failure

The stack was not aligned as expected for `buddy_allocator_init` when
`-o:speed` was enabled, making this a test failure that only appeared
with optimizations enabled.

The data is now aligned specifically, as it should be.
---
 tests/core/mem/test_core_mem.odin | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/tests/core/mem/test_core_mem.odin b/tests/core/mem/test_core_mem.odin
index c1cb59c68..9d64e50a3 100644
--- a/tests/core/mem/test_core_mem.odin
+++ b/tests/core/mem/test_core_mem.odin
@@ -282,13 +282,18 @@ test_dynamic_arena :: proc(t: ^testing.T) {
 
 @test
 test_buddy :: proc(t: ^testing.T) {
-	N :: 4096
+	N :: 8192
 	buf: [N]u8
 
+	base := &buf[0]
+	address := mem.align_forward(base, size_of(mem.Buddy_Block))
+	delta := uintptr(address) - uintptr(base)
+
 	ba: mem.Buddy_Allocator
-	mem.buddy_allocator_init(&ba, buf[:], align_of(u8))
-	basic_sanity_test(t, mem.buddy_allocator(&ba), N / 8)
-	basic_sanity_test(t, mem.buddy_allocator(&ba), N / 8)
+
+	mem.buddy_allocator_init(&ba, buf[delta:delta+N/2], size_of(mem.Buddy_Block))
+	basic_sanity_test(t, mem.buddy_allocator(&ba), N / 16)
+	basic_sanity_test(t, mem.buddy_allocator(&ba), N / 16)
 }
 
 @test

From a0efdf26a6fef9d2db8d7659708b8b9fb142af32 Mon Sep 17 00:00:00 2001
From: Feoramund <161657516+Feoramund@users.noreply.github.com>
Date: Tue, 22 Jul 2025 10:52:55 -0400
Subject: [PATCH 2/2] mem: Clarify `Buddy_Allocator` requirements

---
 core/mem/allocators.odin | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/core/mem/allocators.odin b/core/mem/allocators.odin
index 0eacb1b65..cb9301f60 100644
--- a/core/mem/allocators.odin
+++ b/core/mem/allocators.odin
@@ -2223,6 +2223,9 @@ Initialize a buddy allocator.
 
 This procedure initializes the buddy allocator `b` with a backing buffer `data`
 and block alignment specified by `alignment`.
+
+`alignment` may be any power of two, but the backing buffer must be aligned to
+at least `size_of(Buddy_Block)`.
 */
 buddy_allocator_init :: proc(b: ^Buddy_Allocator, data: []byte, alignment: uint, loc := #caller_location) {
 	assert(data != nil)
@@ -2233,7 +2236,7 @@ buddy_allocator_init :: proc(b: ^Buddy_Allocator, data: []byte, alignment: uint,
 		alignment = size_of(Buddy_Block)
 	}
 	ptr := raw_data(data)
-	assert(uintptr(ptr) % uintptr(alignment) == 0, "data is not aligned to minimum alignment", loc)
+	assert(uintptr(ptr) % uintptr(alignment) == 0, "The data is not aligned to the minimum alignment, which must be at least `size_of(Buddy_Block)`.", loc)
 	b.head = (^Buddy_Block)(ptr)
 	b.head.size = len(data)
 	b.head.is_free = true