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Commit b4013fde authored by Arvind Sankar's avatar Arvind Sankar Committed by Greg Kroah-Hartman
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efi/x86: Free efi_pgd with free_pages() 

[ Upstream commit c2fe61d8be491ff8188edaf22e838f819999146b ]

Commit

  d9e9a641 ("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

    06ace26f ("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.

Fixes: d9e9a641 ("x86/mm/pti: Allocate a separate user PGD")
Link: https://lore.kernel.org/r/20201110163919.1134431-1-nivedita@alum.mit.edu


Signed-off-by: default avatarArvind Sankar <nivedita@alum.mit.edu>
Signed-off-by: default avatarArd Biesheuvel <ardb@kernel.org>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent 088ad76f

arch/x86/platform/efi/efi_64.c

+13 −11
Original line number Diff line number Diff line
@@ -214,28 +214,30 @@ 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;

}



/*