On Tue, 10 Nov 2020 at 17:39, Arvind Sankar <nivedita@xxxxxxxxxxxx> wrote:
>
> Commit
> d9e9a6418065 ("x86/mm/pti: Allocate a separate user PGD")
> changed the PGD allocation to allocate PGD_ALLOCATION_ORDER pages, so in
> the error path it should be freed using free_pages() rather than
> free_page().
>
> Commit
> 06ace26f4e6f ("x86/efi: Free efi_pgd with free_pages()")
> fixed one instance of this, but missed another.
>
> Move the freeing out-of-line to avoid code duplication and fix this bug.
>
> Signed-off-by: Arvind Sankar <nivedita@xxxxxxxxxxxx>
> Fixes: d9e9a6418065 ("x86/mm/pti: Allocate a separate user PGD")
Thanks Arvind. I'll queue this as a fix.
> ---
> arch/x86/platform/efi/efi_64.c | 24 +++++++++++++-----------
> 1 file changed, 13 insertions(+), 11 deletions(-)
>
> diff --git a/arch/x86/platform/efi/efi_64.c b/arch/x86/platform/efi/efi_64.c
> index 8f5759df7776..e1e8d4e3a213 100644
> --- a/arch/x86/platform/efi/efi_64.c
> +++ b/arch/x86/platform/efi/efi_64.c
> @@ -78,28 +78,30 @@ int __init efi_alloc_page_tables(void)
> gfp_mask = GFP_KERNEL | __GFP_ZERO;
> efi_pgd = (pgd_t *)__get_free_pages(gfp_mask, PGD_ALLOCATION_ORDER);
> if (!efi_pgd)
> - return -ENOMEM;
> + goto fail;
>
> pgd = efi_pgd + pgd_index(EFI_VA_END);
> p4d = p4d_alloc(&init_mm, pgd, EFI_VA_END);
> - if (!p4d) {
> - free_page((unsigned long)efi_pgd);
> - return -ENOMEM;
> - }
> + if (!p4d)
> + goto free_pgd;
>
> pud = pud_alloc(&init_mm, p4d, EFI_VA_END);
> - if (!pud) {
> - if (pgtable_l5_enabled())
> - free_page((unsigned long) pgd_page_vaddr(*pgd));
> - free_pages((unsigned long)efi_pgd, PGD_ALLOCATION_ORDER);
> - return -ENOMEM;
> - }
> + if (!pud)
> + goto free_p4d;
>
> efi_mm.pgd = efi_pgd;
> mm_init_cpumask(&efi_mm);
> init_new_context(NULL, &efi_mm);
>
> return 0;
> +
> +free_p4d:
> + if (pgtable_l5_enabled())
> + free_page((unsigned long)pgd_page_vaddr(*pgd));
> +free_pgd:
> + free_pages((unsigned long)efi_pgd, PGD_ALLOCATION_ORDER);
> +fail:
> + return -ENOMEM;
> }
>
> /*
> --
> 2.26.2
>
