Re: [PATCH] libexfat: fix return value of exfat_check_written_data()

On Sat, Aug 8, 2026 at 3:58 PM David Timber <[email protected]> wrote:
>
> In exfat_check_written_data(), the return value of posix_memalign() is
> only used to check if the memory allocation failed and the errno is
> returned from the function. However, according to posix_memalign(3),
> errno shouldn't be set by posix_memalign() at all.
>
> Overflows and invalid allocation lengths are already checked with
> assert() beforehand. Therefore, EINVAL should never be returned from
> posix_memalign(). So, always return -ENOMEM if allocation fails.
>
> Note that currently, this patch doesn't really fix any issue because
> with all the current Linux libc implementations(glibc and musl), errno
> is set for ENOMEM cases in posix_memalign() anyway. This patch is only
> to fix potential undefined behaviour on other POSIX platforms in the
> future.
>
> Fixes: 78e398e37ba5 ("exfatprogs: Fix and improve verify written zeros (memory optimisations)")
> Signed-off-by: David Timber <[email protected]>
Applied it to #exfat-next.
Thanks!