[PATCH] libiberty: Make `objalloc_free' `free'-like WRT null pointer

[Andrew Pinski]

On Wed, Jan 7, 2026 at 1:31 AM Maciej W. Rozycki <macro@redhat.com> wrote:
>
> Inspired by a suggestion from Jan Beulich to make one of `objalloc_free'
> callers `free'-like with respect to null pointer argument handling make
> the function return with no action taken rather than crashing when such
> a pointer is passed.  This is to make the API consistent with ISO C and
> to relieve all the callers from having to check for a null pointer.
>
>         libiberty/
>         * objalloc.c (objalloc_free): Don't use the pointer passed if
>         null.
> ---
> Hi,
>
>  This has been raised in a binutils patch review[1].  OK to apply, and
> then right away, since libiberty is an auxiliary library and technically
> not a part of the compiler suite, plus the change should be trivially
> safe?
>
> References:
>
> [1] "BFD: Prevent a crash on freeing a BFD's uninitialized section hash",
>     <https://inbox.sourceware.org/binutils/23685606-02a1-4416-978a-3c9907c5a171@suse.com/>.
>
>   Maciej
> ---
>  libiberty/objalloc.c |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> binutils-libiberty-objalloc-free-null.diff
> Index: binutils-gdb/libiberty/objalloc.c
> ===================================================================
> --- binutils-gdb.orig/libiberty/objalloc.c
> +++ binutils-gdb/libiberty/objalloc.c
> @@ -178,7 +178,7 @@ objalloc_free (struct objalloc *o)
>  {
>    struct objalloc_chunk *l;
>
> -  l = (struct objalloc_chunk *) o->chunks;
> +  l = o != NULL ? (struct objalloc_chunk *) o->chunks : NULL;

I think the following would be cleaner and easier to understand:
```
/*  Handle a nullptr as being a no-op. */
if (o == NULL)
  return;
l = (struct objalloc_chunk *) o->chunks;
```

Ok with that change.

Thanks,
Andrew

>    while (l != NULL)
>      {
>        struct objalloc_chunk *next;
>