From: David Carlier Date: Wed, 15 Apr 2026 05:23:00 +0000 (+0100) Subject: mm/memfd_luo: report error when restoring a folio fails mid-loop X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=0fb1daf0b78d0e23b63b6b65de56d4a3fd83bc14;p=thirdparty%2Fkernel%2Fstable.git mm/memfd_luo: report error when restoring a folio fails mid-loop memfd_luo_retrieve_folios() initialises err to -EIO, but the per-iteration calls to mem_cgroup_charge(), shmem_add_to_page_cache() and shmem_inode_acct_blocks() reuse and overwrite err. Once any iteration completes successfully, err becomes zero. If a later iteration's kho_restore_folio() returns NULL, the failure path jumps to put_folios without resetting err, so the function returns 0. The caller memfd_luo_retrieve() then takes the success path, sets args->file and reports the restore as successful, leaving userspace with a partially populated memfd and no indication that anything went wrong. Set err to -EIO in the kho_restore_folio() failure branch so the error is propagated to the caller. Signed-off-by: David Carlier Reviewed-by: Pratyush Yadav Fixes: b3749f174d68 ("mm: memfd_luo: allow preserving memfd") Link: https://patch.msgid.link/20260415052300.362539-1-devnexen@gmail.com Signed-off-by: Mike Rapoport (Microsoft) --- diff --git a/mm/memfd_luo.c b/mm/memfd_luo.c index b02b503c750d..35d1247281e0 100644 --- a/mm/memfd_luo.c +++ b/mm/memfd_luo.c @@ -427,6 +427,7 @@ static int memfd_luo_retrieve_folios(struct file *file, if (!folio) { pr_err("Unable to restore folio at physical address: %llx\n", phys); + err = -EIO; goto put_folios; } index = pfolio->index;