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Message-ID: <daffa3ff-5016-732d-f842-bdeed5e6a0de@redhat.com>
Date: Thu, 4 Aug 2022 13:01:06 +0200
From: David Hildenbrand <david@...hat.com>
To: Peter Xu <peterx@...hat.com>, linux-kernel@...r.kernel.org,
linux-mm@...ck.org
Cc: Yang Shi <shy828301@...il.com>,
Andrew Morton <akpm@...ux-foundation.org>,
Nadav Amit <nadav.amit@...il.com>,
Konstantin Khlebnikov <khlebnikov@...nvz.org>
Subject: Re: [PATCH] mm/smaps: Don't access young/dirty bit if pte unpresent
On 04.08.22 00:03, Peter Xu wrote:
> These bits should only be valid when the ptes are present. Introducing two
> booleans for it and set it to false when !pte_present().
>
> Cc: Konstantin Khlebnikov <khlebnikov@...nvz.org>
> Fixes: b1d4d9e0cbd0 ("proc/smaps: carefully handle migration entries", 2012-05-31)
> Signed-off-by: Peter Xu <peterx@...hat.com>
> ---
> fs/proc/task_mmu.c | 7 ++++---
> 1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
> index 9913f3be9fd2..482f91577f8c 100644
> --- a/fs/proc/task_mmu.c
> +++ b/fs/proc/task_mmu.c
> @@ -527,10 +527,12 @@ static void smaps_pte_entry(pte_t *pte, unsigned long addr,
> struct vm_area_struct *vma = walk->vma;
> bool locked = !!(vma->vm_flags & VM_LOCKED);
> struct page *page = NULL;
> - bool migration = false;
> + bool migration = false, young = false, dirty = false;
>
> if (pte_present(*pte)) {
> page = vm_normal_page(vma, addr, *pte);
> + young = pte_young(*pte);
> + dirty = pte_dirty(*pte);
> } else if (is_swap_pte(*pte)) {
> swp_entry_t swpent = pte_to_swp_entry(*pte);
>
> @@ -560,8 +562,7 @@ static void smaps_pte_entry(pte_t *pte, unsigned long addr,
> if (!page)
> return;
>
> - smaps_account(mss, page, false, pte_young(*pte), pte_dirty(*pte),
> - locked, migration);
> + smaps_account(mss, page, false, young, dirty, locked, migration);
> }
>
> #ifdef CONFIG_TRANSPARENT_HUGEPAGE
Reviewed-by: David Hildenbrand <david@...hat.com>
--
Thanks,
David / dhildenb
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