On Tue, Aug 25, 2020 at 01:03:53PM +0530, Naresh Kamboju wrote:
> On Mon, 24 Aug 2020 at 16:36, Matthew Wilcox <willy@xxxxxxxxxxxxx> wrote:
> >
> > On Mon, Aug 24, 2020 at 03:14:55PM +0530, Naresh Kamboju wrote:
> > > [ 67.545247] BUG: Bad page state in process true pfn:a8fed
> > > [ 67.550767] page:9640c0ab refcount:0 mapcount:-1024
> >
> > Somebody freed a page table without calling __ClearPageTable() on it.
>
> After running git bisect on this problem,
> The first suspecting of this problem on arm architecture this patch.
> 424efe723f7717430bec7c93b4d28bba73e31cf6
> ("mm: account PMD tables like PTE tables ")
>
> Reported-by: Naresh Kamboju <naresh.kamboju@xxxxxxxxxx>
> Reported-by: Anders Roxell <anders.roxell@xxxxxxxxxx>
Can you please check if this fix helps?
diff --git a/arch/arm/include/asm/tlb.h b/arch/arm/include/asm/tlb.h
index 9415222b49ad..b8cbe03ad260 100644
--- a/arch/arm/include/asm/tlb.h
+++ b/arch/arm/include/asm/tlb.h
@@ -59,6 +59,7 @@ __pmd_free_tlb(struct mmu_gather *tlb, pmd_t *pmdp, unsigned long addr)
#ifdef CONFIG_ARM_LPAE
struct page *page = virt_to_page(pmdp);
+ pgtable_pmd_page_dtor(page);
tlb_remove_table(tlb, page);
#endif
}
> Additional information:
> We have tested linux next by reverting this patch and confirmed
> that the reported BUG is not reproduced.
>
> These configs enabled on the running device,
>
> CONFIG_TRANSPARENT_HUGEPAGE=y
> CONFIG_TRANSPARENT_HUGEPAGE_MADVISE=y
>
>
> -- Suspecting patch --
> commit 424efe723f7717430bec7c93b4d28bba73e31cf6
> Author: Matthew Wilcox <willy@xxxxxxxxxxxxx>
> Date: Thu Aug 20 10:01:30 2020 +1000
>
> mm: account PMD tables like PTE tables
>
> We account the PTE level of the page tables to the process in order to
> make smarter OOM decisions and help diagnose why memory is fragmented.
> For these same reasons, we should account pages allocated for PMDs. With
> larger process address spaces and ASLR, the number of PMDs in use is
> higher than it used to be so the inaccuracy is starting to matter.
>
> Link: http://lkml.kernel.org/r/20200627184642.GF25039@xxxxxxxxxxxxxxxxxxxx
> Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
> Reviewed-by: Mike Rapoport <rppt@xxxxxxxxxxxxx>
> Cc: Abdul Haleem <abdhalee@xxxxxxxxxxxxxxxxxx>
> Cc: Andy Lutomirski <luto@xxxxxxxxxx>
> Cc: Arnd Bergmann <arnd@xxxxxxxx>
> Cc: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
> Cc: Joerg Roedel <joro@xxxxxxxxxx>
> Cc: Max Filippov <jcmvbkbc@xxxxxxxxx>
> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
> Cc: Satheesh Rajendran <sathnaga@xxxxxxxxxxxxxxxxxx>
> Cc: Stafford Horne <shorne@xxxxxxxxx>
> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> Signed-off-by: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx>
>
> diff --git a/include/linux/mm.h b/include/linux/mm.h
> index b0a15ee77b8a..a4e5b806347c 100644
> --- a/include/linux/mm.h
> +++ b/include/linux/mm.h
> @@ -2239,7 +2239,7 @@ static inline spinlock_t *pmd_lockptr(struct
> mm_struct *mm, pmd_t *pmd)
> return ptlock_ptr(pmd_to_page(pmd));
> }
>
> -static inline bool pgtable_pmd_page_ctor(struct page *page)
> +static inline bool pmd_ptlock_init(struct page *page)
> {
> #ifdef CONFIG_TRANSPARENT_HUGEPAGE
> page->pmd_huge_pte = NULL;
> @@ -2247,7 +2247,7 @@ static inline bool pgtable_pmd_page_ctor(struct
> page *page)
> return ptlock_init(page);
> }
>
> -static inline void pgtable_pmd_page_dtor(struct page *page)
> +static inline void pmd_ptlock_free(struct page *page)
> {
> #ifdef CONFIG_TRANSPARENT_HUGEPAGE
> VM_BUG_ON_PAGE(page->pmd_huge_pte, page);
> @@ -2264,8 +2264,8 @@ static inline spinlock_t *pmd_lockptr(struct
> mm_struct *mm, pmd_t *pmd)
> return &mm->page_table_lock;
> }
>
> -static inline bool pgtable_pmd_page_ctor(struct page *page) { return true; }
> -static inline void pgtable_pmd_page_dtor(struct page *page) {}
> +static inline bool pmd_ptlock_init(struct page *page) { return true; }
> +static inline void pmd_ptlock_free(struct page *page) {}
>
> #define pmd_huge_pte(mm, pmd) ((mm)->pmd_huge_pte)
>
> @@ -2278,6 +2278,22 @@ static inline spinlock_t *pmd_lock(struct
> mm_struct *mm, pmd_t *pmd)
> return ptl;
> }
>
> +static inline bool pgtable_pmd_page_ctor(struct page *page)
> +{
> + if (!pmd_ptlock_init(page))
> + return false;
> + __SetPageTable(page);
> + inc_zone_page_state(page, NR_PAGETABLE);
> + return true;
> +}
> +
> +static inline void pgtable_pmd_page_dtor(struct page *page)
> +{
> + pmd_ptlock_free(page);
> + __ClearPageTable(page);
> + dec_zone_page_state(page, NR_PAGETABLE);
> +}
> +
> /*
> * No scalability reason to split PUD locks yet, but follow the same pattern
> * as the PMD locks to make it easier if we decide to. The VM should not be
>
>
>
>
> - Naresh
--
Sincerely yours,
Mike.
