On Thu, Aug 06 2026, Giorgi Tchankvetadze wrote:
> From: Giorgi Tchankvetadze <[email protected]>
>
> memfd_luo_retrieve_folios() logs "folio index %ld" on its error paths
> but passes the loop counter 'i' instead of the folio's actual index
> held in the local 'index' variable (pfolio->index).
>
> Pass 'index' to the three pr_err() calls so the logged index matches
> the folio that actually failed. Since the saved index is a u64, use %llu with
> an
> unsigned long long cast when printing it.
>
> Fixes: b3749f174d68 ("mm: memfd_luo: allow preserving memfd")
> Signed-off-by: Giorgi Tchankvetadze <[email protected]>
> ---
> mm/memfd_luo.c | 12 ++++++------
> 1 file changed, 6 insertions(+), 6 deletions(-)
>
> diff --git a/mm/memfd_luo.c b/mm/memfd_luo.c
> index 59de210bee5f..652dd21e6ef0 100644
> --- a/mm/memfd_luo.c
> +++ b/mm/memfd_luo.c
> @@ -451,16 +451,16 @@ static int memfd_luo_retrieve_folios(struct file *file,
>
> err = mem_cgroup_charge(folio, NULL, mapping_gfp_mask(mapping));
> if (err) {
> - pr_err("shmem: failed to charge folio index %ld: %d\n",
> - i, err);
> + pr_err("shmem: failed to charge folio index %llu: %d\n",
> + (unsigned long long)index, err);
Why the cast here? u64 is always printed by %llu. See
Documentation/core-api/printk-formats.rst.
> goto unlock_folio;
> }
>
> err = shmem_add_to_page_cache(folio, mapping, index, NULL,
> mapping_gfp_mask(mapping));
> if (err) {
> - pr_err("shmem: failed to add to page cache folio index
> %ld: %d\n",
> - i, err);
> + pr_err("shmem: failed to add to page cache folio index
> %llu: %d\n",
> + (unsigned long long)index, err);
> goto unlock_folio;
> }
>
> @@ -472,8 +472,8 @@ static int memfd_luo_retrieve_folios(struct file *file,
> npages = folio_nr_pages(folio);
> err = shmem_inode_acct_blocks(inode, npages);
> if (err) {
> - pr_err("shmem: failed to account folio index %ld(%ld
> pages): %d\n",
> - i, npages, err);
> + pr_err("shmem: failed to account folio index %llu(%ld
> pages): %d\n",
> + (unsigned long long)index, npages, err);
> goto remove_from_cache;
> }
--
Regards,
Pratyush Yadav
