From 5e8e90d28f5ac6715a2568f337234088fea1fdb3 Mon Sep 17 00:00:00 2001
From: Jan Niehusmann <jan@gondor.com>
Date: Wed, 28 Jan 2026 11:05:04 +0000
Subject: [PATCH] Fix iter_blocks on oddly sized or unaligned blocks

If len < GRANULARITY * 2, insert_free_block_ptr doesn't insert another block:

```
          let len = if let Some(x) = len
              .checked_sub((start as usize).wrapping_sub(unaligned_start as usize))
              .filter(|&x| x >= GRANULARITY * 2)
          {
              // Round down
              x & !(GRANULARITY - 1)
          } else {
              // The block is too small
              return None;
          };
```

This can happen if the block being added has an odd size (not a multiple
of GRANULARITY * 2) or is unaligned.

Therefore, iter_blocks must also skip remaining lengths smaller than this.

I think this is the root cause for a panic we observed in
https://github.com/rust-embedded/embedded-alloc/issues/121
---
 crates/rlsf/src/tlsf.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/crates/rlsf/src/tlsf.rs b/crates/rlsf/src/tlsf.rs
index e3afdad..f16a5b5 100644
--- a/crates/rlsf/src/tlsf.rs
+++ b/crates/rlsf/src/tlsf.rs
@@ -1545,7 +1545,7 @@ impl<'pool, FLBitmap: BinInteger, SLBitmap: BinInteger, const FLLEN: usize, cons
         core::iter::from_fn(move || {
             let _ = &start;
 
-            if len == 0 {
+            if len < GRANULARITY * 2 {
                 None
             } else {
                 let block_hdr = &*(start.0 as *const BlockHdr);