| Message ID | 20170412140459.21824-2-punit.agrawal@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 4/12/2017 8:04 AM, Punit Agrawal wrote: > When memory failure is enabled, a poisoned hugepage pte is marked as a > swap entry. huge_pte_offset() does not return the poisoned page table > entries when it encounters PUD/PMD hugepages. > > This behaviour of huge_pte_offset() leads to error such as below when > munmap is called on poisoned hugepages. > > [ 344.165544] mm/pgtable-generic.c:33: bad pmd 000000083af00074. > > Fix huge_pte_offset() to return the poisoned pte which is then > appropriately handled by the generic layer code. > > Signed-off-by: Punit Agrawal <punit.agrawal@arm.com> > Cc: Catalin Marinas <catalin.marinas@arm.com> > Cc: Steve Capper <steve.capper@arm.com> > Cc: David Woods <dwoods@mellanox.com> Tested-by: Tyler Baicar <tbaicar@codeaurora.org> Thanks, Tyler > --- > arch/arm64/mm/hugetlbpage.c | 20 +++++++++++++++----- > 1 file changed, 15 insertions(+), 5 deletions(-) > > diff --git a/arch/arm64/mm/hugetlbpage.c b/arch/arm64/mm/hugetlbpage.c > index 7514a000e361..5f1832165d69 100644 > --- a/arch/arm64/mm/hugetlbpage.c > +++ b/arch/arm64/mm/hugetlbpage.c > @@ -143,15 +143,24 @@ pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr) > pr_debug("%s: addr:0x%lx pgd:%p\n", __func__, addr, pgd); > if (!pgd_present(*pgd)) > return NULL; > - pud = pud_offset(pgd, addr); > - if (!pud_present(*pud)) > - return NULL; > > - if (pud_huge(*pud)) > + pud = pud_offset(pgd, addr); > + /* > + * In case of HW Poisoning, a hugepage pud/pmd can contain > + * poisoned entries. Poisoned entries are marked as swap > + * entries. > + * > + * For puds/pmds that are not present, check to see if it > + * could be a swap entry (!present and !none). > + */ > + if ((!pte_present(pud_pte(*pud)) && !pud_none(*pud)) || pud_huge(*pud)) > return (pte_t *)pud; > + > pmd = pmd_offset(pud, addr); > - if (!pmd_present(*pmd)) > + if (pmd_none(*pmd)) > return NULL; > + if (!pmd_present(*pmd) && !pmd_none(*pmd)) > + return (pte_t *)pmd; > > if (pte_cont(pmd_pte(*pmd))) { > pmd = pmd_offset( > @@ -160,6 +169,7 @@ pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr) > } > if (pmd_huge(*pmd)) > return (pte_t *)pmd; > + > pte = pte_offset_kernel(pmd, addr); > if (pte_present(*pte) && pte_cont(*pte)) { > pte = pte_offset_kernel(
On Wed, Apr 12, 2017 at 03:04:57PM +0100, Punit Agrawal wrote: > When memory failure is enabled, a poisoned hugepage pte is marked as a > swap entry. huge_pte_offset() does not return the poisoned page table > entries when it encounters PUD/PMD hugepages. > > This behaviour of huge_pte_offset() leads to error such as below when > munmap is called on poisoned hugepages. > > [ 344.165544] mm/pgtable-generic.c:33: bad pmd 000000083af00074. > > Fix huge_pte_offset() to return the poisoned pte which is then > appropriately handled by the generic layer code. > > Signed-off-by: Punit Agrawal <punit.agrawal@arm.com> > Cc: Catalin Marinas <catalin.marinas@arm.com> > Cc: Steve Capper <steve.capper@arm.com> > Cc: David Woods <dwoods@mellanox.com> > --- > arch/arm64/mm/hugetlbpage.c | 20 +++++++++++++++----- > 1 file changed, 15 insertions(+), 5 deletions(-) > > diff --git a/arch/arm64/mm/hugetlbpage.c b/arch/arm64/mm/hugetlbpage.c > index 7514a000e361..5f1832165d69 100644 > --- a/arch/arm64/mm/hugetlbpage.c > +++ b/arch/arm64/mm/hugetlbpage.c > @@ -143,15 +143,24 @@ pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr) > pr_debug("%s: addr:0x%lx pgd:%p\n", __func__, addr, pgd); > if (!pgd_present(*pgd)) > return NULL; > - pud = pud_offset(pgd, addr); > - if (!pud_present(*pud)) > - return NULL; > > - if (pud_huge(*pud)) > + pud = pud_offset(pgd, addr); > + /* > + * In case of HW Poisoning, a hugepage pud/pmd can contain > + * poisoned entries. Poisoned entries are marked as swap > + * entries. > + * > + * For puds/pmds that are not present, check to see if it > + * could be a swap entry (!present and !none). > + */ > + if ((!pte_present(pud_pte(*pud)) && !pud_none(*pud)) || pud_huge(*pud)) > return (pte_t *)pud; Since we use puds as huge pages, can we just change pud_present() to match the pmd_present()? I'd like to see similar checks for pud and pmd, it would be easier to follow. Something like (unchecked): if (pud_none(*pud)) return NULL; /* swap or huge page */ if (!pud_present(*pud) || pud_huge(*pud)) return (pte_t *)pud; /* table; check the next level */ > + > pmd = pmd_offset(pud, addr); > - if (!pmd_present(*pmd)) > + if (pmd_none(*pmd)) > return NULL; > + if (!pmd_present(*pmd) && !pmd_none(*pmd)) > + return (pte_t *)pmd; At this point, we already know that pmd_none(*pmd) is false, no ned to check it again.
Catalin Marinas <catalin.marinas@arm.com> writes: > On Wed, Apr 12, 2017 at 03:04:57PM +0100, Punit Agrawal wrote: >> When memory failure is enabled, a poisoned hugepage pte is marked as a >> swap entry. huge_pte_offset() does not return the poisoned page table >> entries when it encounters PUD/PMD hugepages. >> >> This behaviour of huge_pte_offset() leads to error such as below when >> munmap is called on poisoned hugepages. >> >> [ 344.165544] mm/pgtable-generic.c:33: bad pmd 000000083af00074. >> >> Fix huge_pte_offset() to return the poisoned pte which is then >> appropriately handled by the generic layer code. >> >> Signed-off-by: Punit Agrawal <punit.agrawal@arm.com> >> Cc: Catalin Marinas <catalin.marinas@arm.com> >> Cc: Steve Capper <steve.capper@arm.com> >> Cc: David Woods <dwoods@mellanox.com> >> --- >> arch/arm64/mm/hugetlbpage.c | 20 +++++++++++++++----- >> 1 file changed, 15 insertions(+), 5 deletions(-) >> >> diff --git a/arch/arm64/mm/hugetlbpage.c b/arch/arm64/mm/hugetlbpage.c >> index 7514a000e361..5f1832165d69 100644 >> --- a/arch/arm64/mm/hugetlbpage.c >> +++ b/arch/arm64/mm/hugetlbpage.c >> @@ -143,15 +143,24 @@ pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr) >> pr_debug("%s: addr:0x%lx pgd:%p\n", __func__, addr, pgd); >> if (!pgd_present(*pgd)) >> return NULL; >> - pud = pud_offset(pgd, addr); >> - if (!pud_present(*pud)) >> - return NULL; >> >> - if (pud_huge(*pud)) >> + pud = pud_offset(pgd, addr); >> + /* >> + * In case of HW Poisoning, a hugepage pud/pmd can contain >> + * poisoned entries. Poisoned entries are marked as swap >> + * entries. >> + * >> + * For puds/pmds that are not present, check to see if it >> + * could be a swap entry (!present and !none). >> + */ >> + if ((!pte_present(pud_pte(*pud)) && !pud_none(*pud)) || pud_huge(*pud)) >> return (pte_t *)pud; > > Since we use puds as huge pages, can we just change pud_present() to > match the pmd_present()? I'd like to see similar checks for pud and pmd, > it would be easier to follow. Something like (unchecked): > > if (pud_none(*pud)) > return NULL; > /* swap or huge page */ > if (!pud_present(*pud) || pud_huge(*pud)) > return (pte_t *)pud; > /* table; check the next level */ > >> + >> pmd = pmd_offset(pud, addr); >> - if (!pmd_present(*pmd)) >> + if (pmd_none(*pmd)) >> return NULL; >> + if (!pmd_present(*pmd) && !pmd_none(*pmd)) >> + return (pte_t *)pmd; > > At this point, we already know that pmd_none(*pmd) is false, no ned to > check it again. Indeed - I was avoiding changing the function to drop contiguous hugepage support which follows this hunk. I've made changes locally based on your suggestion and will post a revised version after the merge window. Thanks, Punit
On Thu, May 4, 2017 at 10:55 AM, Punit Agrawal <punit.agrawal@arm.com> wrote: > Indeed - I was avoiding changing the function to drop contiguous > hugepage support which follows this hunk. > > I've made changes locally based on your suggestion and will post a > revised version after the merge window. Punit, will you be able to post a new version that could be a candidate for 4.13?
Timur Tabi <timur@codeaurora.org> writes: > On Thu, May 4, 2017 at 10:55 AM, Punit Agrawal <punit.agrawal@arm.com> wrote: >> Indeed - I was avoiding changing the function to drop contiguous >> hugepage support which follows this hunk. >> >> I've made changes locally based on your suggestion and will post a >> revised version after the merge window. > > Punit, will you be able to post a new version that could be a > candidate for 4.13? Hi Timur, I've just posted v2 for this series. I was testing the patches on rc1 when I saw your mail come through. Please shout out if you notice any problems with the new version. Thanks, Punit
diff --git a/arch/arm64/mm/hugetlbpage.c b/arch/arm64/mm/hugetlbpage.c index 7514a000e361..5f1832165d69 100644 --- a/arch/arm64/mm/hugetlbpage.c +++ b/arch/arm64/mm/hugetlbpage.c @@ -143,15 +143,24 @@ pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr) pr_debug("%s: addr:0x%lx pgd:%p\n", __func__, addr, pgd); if (!pgd_present(*pgd)) return NULL; - pud = pud_offset(pgd, addr); - if (!pud_present(*pud)) - return NULL; - if (pud_huge(*pud)) + pud = pud_offset(pgd, addr); + /* + * In case of HW Poisoning, a hugepage pud/pmd can contain + * poisoned entries. Poisoned entries are marked as swap + * entries. + * + * For puds/pmds that are not present, check to see if it + * could be a swap entry (!present and !none). + */ + if ((!pte_present(pud_pte(*pud)) && !pud_none(*pud)) || pud_huge(*pud)) return (pte_t *)pud; + pmd = pmd_offset(pud, addr); - if (!pmd_present(*pmd)) + if (pmd_none(*pmd)) return NULL; + if (!pmd_present(*pmd) && !pmd_none(*pmd)) + return (pte_t *)pmd; if (pte_cont(pmd_pte(*pmd))) { pmd = pmd_offset( @@ -160,6 +169,7 @@ pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr) } if (pmd_huge(*pmd)) return (pte_t *)pmd; + pte = pte_offset_kernel(pmd, addr); if (pte_present(*pte) && pte_cont(*pte)) { pte = pte_offset_kernel(
When memory failure is enabled, a poisoned hugepage pte is marked as a swap entry. huge_pte_offset() does not return the poisoned page table entries when it encounters PUD/PMD hugepages. This behaviour of huge_pte_offset() leads to error such as below when munmap is called on poisoned hugepages. [ 344.165544] mm/pgtable-generic.c:33: bad pmd 000000083af00074. Fix huge_pte_offset() to return the poisoned pte which is then appropriately handled by the generic layer code. Signed-off-by: Punit Agrawal <punit.agrawal@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Steve Capper <steve.capper@arm.com> Cc: David Woods <dwoods@mellanox.com> --- arch/arm64/mm/hugetlbpage.c | 20 +++++++++++++++----- 1 file changed, 15 insertions(+), 5 deletions(-)