CVE-2024-49872

In the Linux kernel, the following vulnerability has been resolved:

mm/gup: fix memfd_pin_folios alloc race panic

If memfd_pin_folios tries to create a hugetlb page, but someone else already did, then folio gets the value -EEXIST here:

    folio = memfd_alloc_folio(memfd, start_idx);
    if (IS_ERR(folio)) {
            ret = PTR_ERR(folio);
            if (ret != -EEXIST)
                    goto err;

then on the next trip through the "while start_idx" loop we panic here:

    if (folio) {
            folio_put(folio);

To fix, set the folio to NULL on error.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.