2019-07-31 06:03:54

by Christophe Leroy

Subject: [PATCH] powerpc/kasan: fix early boot failure on PPC32

Due to commit 4a6d8cf90017 ("powerpc/mm: don't use pte_alloc_kernel()
until slab is available on PPC32"), pte_alloc_kernel() cannot be used
during early KASAN init.

Fix it by using memblock_alloc() instead.

Reported-by: Erhard F. <[email protected]>
Fixes: 2edb16efc899 ("powerpc/32: Add KASAN support")
Signed-off-by: Christophe Leroy <[email protected]>
---
arch/powerpc/mm/kasan/kasan_init_32.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/mm/kasan/kasan_init_32.c b/arch/powerpc/mm/kasan/kasan_init_32.c
index 0d62be3cba47..74f4555a62ba 100644
--- a/arch/powerpc/mm/kasan/kasan_init_32.c
+++ b/arch/powerpc/mm/kasan/kasan_init_32.c
@@ -21,7 +21,7 @@ static void kasan_populate_pte(pte_t *ptep, pgprot_t prot)
__set_pte_at(&init_mm, va, ptep, pfn_pte(PHYS_PFN(pa), prot), 0);
}

-static int kasan_init_shadow_page_tables(unsigned long k_start, unsigned long k_end)
+static int __ref kasan_init_shadow_page_tables(unsigned long k_start, unsigned long k_end)
{
pmd_t *pmd;
unsigned long k_cur, k_next;
@@ -35,7 +35,10 @@ static int kasan_init_shadow_page_tables(unsigned long k_start, unsigned long k_
if ((void *)pmd_page_vaddr(*pmd) != kasan_early_shadow_pte)
continue;

- new = pte_alloc_one_kernel(&init_mm);
+ if (slab_is_available())
+ new = pte_alloc_one_kernel(&init_mm);
+ else
+ new = memblock_alloc(PTE_FRAG_SIZE, PTE_FRAG_SIZE);

if (!new)
return -ENOMEM;
--
2.13.3

2019-07-31 08:04:02

by Christophe Leroy

Subject: Re: [PATCH] powerpc/kasan: fix early boot failure on PPC32

Le 31/07/2019 à 08:01, Christophe Leroy a écrit :
> Due to commit 4a6d8cf90017 ("powerpc/mm: don't use pte_alloc_kernel()
> until slab is available on PPC32"), pte_alloc_kernel() cannot be used
> during early KASAN init.
>
> Fix it by using memblock_alloc() instead.
>
> Reported-by: Erhard F. <[email protected]>
> Fixes: 2edb16efc899 ("powerpc/32: Add KASAN support")
> Signed-off-by: Christophe Leroy <[email protected]>

Cc: [email protected]

> ---
> arch/powerpc/mm/kasan/kasan_init_32.c | 7 +++++--
> 1 file changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/arch/powerpc/mm/kasan/kasan_init_32.c b/arch/powerpc/mm/kasan/kasan_init_32.c
> index 0d62be3cba47..74f4555a62ba 100644
> --- a/arch/powerpc/mm/kasan/kasan_init_32.c
> +++ b/arch/powerpc/mm/kasan/kasan_init_32.c
> @@ -21,7 +21,7 @@ static void kasan_populate_pte(pte_t *ptep, pgprot_t prot)
> __set_pte_at(&init_mm, va, ptep, pfn_pte(PHYS_PFN(pa), prot), 0);
> }
>
> -static int kasan_init_shadow_page_tables(unsigned long k_start, unsigned long k_end)
> +static int __ref kasan_init_shadow_page_tables(unsigned long k_start, unsigned long k_end)
> {
> pmd_t *pmd;
> unsigned long k_cur, k_next;
> @@ -35,7 +35,10 @@ static int kasan_init_shadow_page_tables(unsigned long k_start, unsigned long k_
> if ((void *)pmd_page_vaddr(*pmd) != kasan_early_shadow_pte)
> continue;
>
> - new = pte_alloc_one_kernel(&init_mm);
> + if (slab_is_available())
> + new = pte_alloc_one_kernel(&init_mm);
> + else
> + new = memblock_alloc(PTE_FRAG_SIZE, PTE_FRAG_SIZE);
>
> if (!new)
> return -ENOMEM;
>

2019-08-02 02:57:16

by Michael Ellerman

Subject: Re: [PATCH] powerpc/kasan: fix early boot failure on PPC32

On Wed, 2019-07-31 at 06:01:42 UTC, Christophe Leroy wrote:
> Due to commit 4a6d8cf90017 ("powerpc/mm: don't use pte_alloc_kernel()
> until slab is available on PPC32"), pte_alloc_kernel() cannot be used
> during early KASAN init.
>
> Fix it by using memblock_alloc() instead.
>
> Reported-by: Erhard F. <[email protected]>
> Fixes: 2edb16efc899 ("powerpc/32: Add KASAN support")
> Signed-off-by: Christophe Leroy <[email protected]>

Applied to powerpc fixes, thanks.

https://git.kernel.org/powerpc/c/d7e23b887f67178c4f840781be7a6aa6aeb52ab1

cheers