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acassis pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/nuttx.git
The following commit(s) were added to refs/heads/master by this push:
new 977f9ed4b8c libs/libc/obstack/lib_obstack_free.c: fix object check
within chunk
977f9ed4b8c is described below
commit 977f9ed4b8c652b258f7a2734efaf85c508ce5f5
Author: Michal Lenc <[email protected]>
AuthorDate: Fri Dec 12 16:29:15 2025 +0100
libs/libc/obstack/lib_obstack_free.c: fix object check within chunk
The original condition incorrectly used &h->chunk instead of
h->chunk in the calculation whether the object is in the chunk. This
could lead to the wrong behavior as the first branch gave incorrect
result and thus sometimes the entire obstack was freed even though
object was not NULL.
The commit also simplifies the logic, we can use pointer arithmetic
here and just do h->chunk + 1 as it gives the same result as
(FAR char *)h->chunk + sizeof(struct _obstack_chunk). This saves
unnecessary cast and sizeof.
The second branch should be less than or equal, not just less than.
This ensures the object is correctly located in the chunk even after
previous obstack_finish was called.
Signed-off-by: Michal Lenc <[email protected]>
Co-authored-by: Karel Kočí <[email protected]>
---
libs/libc/obstack/lib_obstack_free.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)
diff --git a/libs/libc/obstack/lib_obstack_free.c
b/libs/libc/obstack/lib_obstack_free.c
index 751d471c75c..229bb3f1e96 100644
--- a/libs/libc/obstack/lib_obstack_free.c
+++ b/libs/libc/obstack/lib_obstack_free.c
@@ -53,9 +53,13 @@ void obstack_free(FAR struct obstack *h, FAR void *object)
while (h->chunk)
{
- if (object >=
- (FAR void *)((FAR char *)&h->chunk + sizeof(struct _obstack_chunk))
- && object < (FAR void *)h->chunk->limit)
+ /* Object has to be after chunk + chunk' header. We can use pointer
+ * arithmetic here as h->chunk + 1 is the same as
+ * (FAR char *)h->chunk + sizeof(struct _obstack_chunk)
+ */
+
+ if (object >= (FAR void *)(h->chunk + 1)
+ && object <= (FAR void *)h->chunk->limit)
{
/* The object is in this chunk so just move object base.
* Note: this keeps the last chunk allocated. This is desirable
