From: Yang Shi <shy828301@gmail.com>
To: Peter Xu <peterx@redhat.com>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
Andrew Morton <akpm@linux-foundation.org>,
Nadav Amit <nadav.amit@gmail.com>,
David Hildenbrand <david@redhat.com>,
Konstantin Khlebnikov <khlebnikov@openvz.org>
Subject: Re: [PATCH] mm/smaps: Don't access young/dirty bit if pte unpresent
Date: Thu, 4 Aug 2022 10:43:47 -0700 [thread overview]
Message-ID: <CAHbLzkoztB1LNOtNWa=8GPABF5xConGox2D1ebdD97467Ykb1A@mail.gmail.com> (raw)
In-Reply-To: <20220803220329.46299-1-peterx@redhat.com>
On Wed, Aug 3, 2022 at 3:03 PM Peter Xu <peterx@redhat.com> 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@openvz.org>
> Fixes: b1d4d9e0cbd0 ("proc/smaps: carefully handle migration entries", 2012-05-31)
> Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Yang Shi <shy828301@gmail.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
> --
> 2.32.0
>
next prev parent reply other threads:[~2022-08-04 17:44 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-03 22:03 [PATCH] mm/smaps: Don't access young/dirty bit if pte unpresent Peter Xu
2022-08-04 9:02 ` Vlastimil Babka (SUSE)
2022-08-04 11:01 ` David Hildenbrand
2022-08-04 17:43 ` Yang Shi [this message]
2022-08-04 22:40 ` Andrew Morton
2022-08-05 15:52 ` Peter Xu
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