From: Alistair Popple <apopple@nvidia.com>
To: Hugh Dickins <hughd@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Jason Gunthorpe <jgg@nvidia.com>,
Ralph Campbell <rcampbell@nvidia.com>,
Christoph Hellwig <hch@lst.de>, Yang Shi <shy828301@gmail.com>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Shakeel Butt <shakeelb@google.com>,
<linux-kernel@vger.kernel.org>, <linux-mm@kvack.org>
Subject: Re: [PATCH 3/4] mm/rmap: fix new bug: premature return from page_mlock_one()
Date: Thu, 8 Jul 2021 09:14:03 +1000 [thread overview]
Message-ID: <5771626.u1GIez9f9F@nvdebian> (raw)
In-Reply-To: <f71f8523-cba7-3342-40a7-114abc5d1f51@google.com>
Thanks Hugh, evidently I missed this when re-adding the VM_LOCKED check
back.
Reviewed-by: Alistair Popple <apopple@nvidia.com>
On Thursday, 8 July 2021 6:11:24 AM AEST Hugh Dickins wrote:
> In the unlikely race case that page_mlock_one() finds VM_LOCKED has been
> cleared by the time it got page table lock, page_vma_mapped_walk_done()
> must be called before returning, either explicitly, or by a final call
> to page_vma_mapped_walk() - otherwise the page table remains locked.
>
> Fixes: cd62734ca60d ("mm/rmap: split try_to_munlock from try_to_unmap")
> Signed-off-by: Hugh Dickins <hughd@google.com>
> ---
> mm/rmap.c | 11 +++++------
> 1 file changed, 5 insertions(+), 6 deletions(-)
>
> diff --git a/mm/rmap.c b/mm/rmap.c
> index 0e83c3be8568..1235368f0628 100644
> --- a/mm/rmap.c
> +++ b/mm/rmap.c
> @@ -1990,14 +1990,13 @@ static bool page_mlock_one(struct page *page, struct vm_area_struct *vma,
> * this function is never called when PageDoubleMap().
> */
> mlock_vma_page(page);
> + /*
> + * No need to scan further once the page is marked
> + * as mlocked.
> + */
> page_vma_mapped_walk_done(&pvmw);
> + return false;
> }
> -
> - /*
> - * no need to continue scanning other vma's if the page has
> - * been locked.
> - */
> - return false;
> }
>
> return true;
>
next prev parent reply other threads:[~2021-07-07 23:14 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-07 20:06 [PATCH 1/4] mm/rmap: fix comments left over from recent changes Hugh Dickins
2021-07-07 20:08 ` [PATCH 2/4] mm/rmap: fix old bug: munlocking THP missed other mlocks Hugh Dickins
2021-07-07 20:53 ` Shakeel Butt
2021-07-08 13:58 ` Kirill A. Shutemov
2021-07-09 2:50 ` Hugh Dickins
2021-07-09 10:56 ` Kirill A. Shutemov
2021-07-07 20:11 ` [PATCH 3/4] mm/rmap: fix new bug: premature return from page_mlock_one() Hugh Dickins
2021-07-07 20:22 ` Shakeel Butt
2021-07-07 23:14 ` Alistair Popple [this message]
2021-07-07 20:13 ` [PATCH 4/4] mm/rmap: try_to_migrate() skip zone_device !device_private Hugh Dickins
2021-07-07 20:54 ` Shakeel Butt
2021-07-07 23:25 ` Alistair Popple
2021-07-07 20:22 ` [PATCH 1/4] mm/rmap: fix comments left over from recent changes Shakeel Butt
2021-07-07 21:26 ` Yang Shi
2021-07-07 21:29 ` Yang Shi
2021-07-07 23:34 ` Alistair Popple
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