From: Miaohe Lin <linmiaohe@huawei.com>
To: Peter Xu <peterx@redhat.com>
Cc: <akpm@linux-foundation.org>, <willy@infradead.org>,
<vbabka@suse.cz>, <dhowells@redhat.com>, <neilb@suse.de>,
<david@redhat.com>, <apopple@nvidia.com>, <surenb@google.com>,
<minchan@kernel.org>, <sfr@canb.auug.org.au>,
<rcampbell@nvidia.com>, <naoya.horiguchi@nec.com>,
<linux-mm@kvack.org>, <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2] mm/swapfile: unuse_pte can map random data if swap read fails
Date: Wed, 20 Apr 2022 14:21:27 +0800 [thread overview]
Message-ID: <8e01e276-c956-2486-c55f-c689f33a9106@huawei.com> (raw)
In-Reply-To: <Yl8rZkhU/B0iE2ob@xz-m1.local>
On 2022/4/20 5:36, Peter Xu wrote:
> On Sat, Apr 16, 2022 at 11:05:49AM +0800, Miaohe Lin wrote:
>> @@ -1797,6 +1797,17 @@ static int unuse_pte(struct vm_area_struct *vma, pmd_t *pmd,
>> goto out;
>> }
>>
>> + if (unlikely(!PageUptodate(page))) {
>> + pte_t pteval;
>> +
>> + dec_mm_counter(vma->vm_mm, MM_SWAPENTS);
>> + pteval = swp_entry_to_pte(make_swapin_error_entry(page));
>> + set_pte_at(vma->vm_mm, addr, pte, pteval);
>> + swap_free(entry);
>> + ret = 0;
>> + goto out;
>> + }
>> +
>> /* See do_swap_page() */
>> BUG_ON(!PageAnon(page) && PageMappedToDisk(page));
>> BUG_ON(PageAnon(page) && PageAnonExclusive(page));
>
> Totally off-topic, but.. today when I was looking at the unuse path I just
> found that the swp bits could have got lost for either soft-dirty and
> uffd-wp here? A quick patch attached.
Am I supposed to test-and-send this patch? The patch looks good to me except the
build error pointed out by kernel test robot.
>
> Maybe at some point we should start to have some special helpers for
> set_pte_at() when we're converting between present/non-present ptes, so as
> to make sure all these will always be taken care of properly.
That will be helpful. There are many places doing the similar thing.
>
Thanks!
next prev parent reply other threads:[~2022-04-20 6:21 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-16 3:05 [PATCH v2] mm/swapfile: unuse_pte can map random data if swap read fails Miaohe Lin
2022-04-19 3:51 ` Alistair Popple
2022-04-19 7:29 ` Miaohe Lin
2022-04-19 7:39 ` David Hildenbrand
2022-04-19 8:08 ` Alistair Popple
2022-04-19 11:14 ` David Hildenbrand
2022-04-19 16:16 ` Peter Xu
2022-04-19 11:14 ` Miaohe Lin
2022-04-19 7:53 ` Alistair Popple
2022-04-19 11:26 ` Miaohe Lin
2022-04-20 0:25 ` Alistair Popple
2022-04-20 6:15 ` Miaohe Lin
2022-04-20 7:07 ` David Hildenbrand
2022-04-20 8:37 ` Miaohe Lin
2022-04-19 7:37 ` David Hildenbrand
2022-04-19 11:21 ` Miaohe Lin
2022-04-19 11:46 ` David Hildenbrand
2022-04-19 12:00 ` Miaohe Lin
2022-04-19 12:12 ` David Hildenbrand
2022-04-19 12:45 ` Miaohe Lin
2022-04-19 21:36 ` Peter Xu
2022-04-20 5:56 ` [PATCH] mm/swap: Fix lost swap bits in unuse_pte() kernel test robot
2022-04-20 6:23 ` Miaohe Lin
2022-04-20 6:39 ` [kbuild-all] " Philip Li
2022-04-20 6:52 ` Miaohe Lin
2022-04-20 6:48 ` Chen, Rong A
2022-04-20 6:56 ` Miaohe Lin
2022-04-20 6:21 ` Miaohe Lin [this message]
2022-04-20 13:32 ` [PATCH v2] mm/swapfile: unuse_pte can map random data if swap read fails Peter Xu
2022-04-21 1:50 ` Miaohe Lin
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