Re: [mainline][Oops][bisected 2ba3e6 ] 5.7.0 boot fails with kernel panic on powerpc

From: Abdul Haleem
Date: Thu Jun 04 2020 - 01:59:08 EST


On Wed, 2020-06-03 at 15:32 +0200, Joerg Roedel wrote:
> On Wed, Jun 03, 2020 at 04:20:57PM +0530, Abdul Haleem wrote:
> > @Joerg, Could you please have a look?
>
> Can you please try the attached patch?

Thanks Joerg, The given patch fixes the boot problem.

Please add Reported-by in fix commit.

Reported-by: Abdul Haleem <abdhalee@xxxxxxxxxxxxxxxxxx>

>
> diff --git a/include/asm-generic/5level-fixup.h b/include/asm-generic/5level-fixup.h
> index 58046ddc08d0..afbab31fbd7e 100644
> --- a/include/asm-generic/5level-fixup.h
> +++ b/include/asm-generic/5level-fixup.h
> @@ -17,6 +17,11 @@
> ((unlikely(pgd_none(*(p4d))) && __pud_alloc(mm, p4d, address)) ? \
> NULL : pud_offset(p4d, address))
>
> +#define pud_alloc_track(mm, p4d, address, mask) \
> + ((unlikely(pgd_none(*(p4d))) && \
> + (__pud_alloc(mm, p4d, address) || ({*(mask)|=PGTBL_P4D_MODIFIED;0;})))? \
> + NULL : pud_offset(p4d, address))
> +
> #define p4d_alloc(mm, pgd, address) (pgd)
> #define p4d_alloc_track(mm, pgd, address, mask) (pgd)
> #define p4d_offset(pgd, start) (pgd)
> diff --git a/include/linux/mm.h b/include/linux/mm.h
> index 7e07f4f490cb..d46bf03b804f 100644
> --- a/include/linux/mm.h
> +++ b/include/linux/mm.h
> @@ -2088,35 +2088,35 @@ static inline pud_t *pud_alloc(struct mm_struct *mm, p4d_t *p4d,
> NULL : pud_offset(p4d, address);
> }
>
> -static inline p4d_t *p4d_alloc_track(struct mm_struct *mm, pgd_t *pgd,
> +static inline pud_t *pud_alloc_track(struct mm_struct *mm, p4d_t *p4d,
> unsigned long address,
> pgtbl_mod_mask *mod_mask)
> -
> {
> - if (unlikely(pgd_none(*pgd))) {
> - if (__p4d_alloc(mm, pgd, address))
> + if (unlikely(p4d_none(*p4d))) {
> + if (__pud_alloc(mm, p4d, address))
> return NULL;
> - *mod_mask |= PGTBL_PGD_MODIFIED;
> + *mod_mask |= PGTBL_P4D_MODIFIED;
> }
>
> - return p4d_offset(pgd, address);
> + return pud_offset(p4d, address);
> }
>
> -#endif /* !__ARCH_HAS_5LEVEL_HACK */
> -
> -static inline pud_t *pud_alloc_track(struct mm_struct *mm, p4d_t *p4d,
> +static inline p4d_t *p4d_alloc_track(struct mm_struct *mm, pgd_t *pgd,
> unsigned long address,
> pgtbl_mod_mask *mod_mask)
> +
> {
> - if (unlikely(p4d_none(*p4d))) {
> - if (__pud_alloc(mm, p4d, address))
> + if (unlikely(pgd_none(*pgd))) {
> + if (__p4d_alloc(mm, pgd, address))
> return NULL;
> - *mod_mask |= PGTBL_P4D_MODIFIED;
> + *mod_mask |= PGTBL_PGD_MODIFIED;
> }
>
> - return pud_offset(p4d, address);
> + return p4d_offset(pgd, address);
> }
>
> +#endif /* !__ARCH_HAS_5LEVEL_HACK */
> +
> static inline pmd_t *pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address)
> {
> return (unlikely(pud_none(*pud)) && __pmd_alloc(mm, pud, address))?


--
Regard's

Abdul Haleem
IBM Linux Technology Centre