From: Hongfu Li <hongfu.li@linux.dev>
To: "Lorenzo Stoakes (ARM)" <ljs@kernel.org>
Cc: hongfu.li@linux.dev, akpm@linux-foundation.org,
liam@infradead.org, vbabka@kernel.org, jannh@google.com,
pfalcato@suse.de, david@kernel.org, jeffxu@chromium.org,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Hongfu Li <lihongfu@kylinos.cn>
Subject: Re: [PATCH] mm/mseal: Fix range_contains_unmapped() ignoring its mm argument
Date: Fri, 17 Jul 2026 09:34:55 +0800 [thread overview]
Message-ID: <cd922756-a4b5-4666-af7a-4071ef902375@linux.dev> (raw)
In-Reply-To: <alit0N1CBEllrD0U@lucifer>
Hi,
On 7/16/26 6:19 PM, Lorenzo Stoakes (ARM) wrote:
> On Thu, Jul 16, 2026 at 05:33:47PM +0800, Hongfu Li wrote:
>> From: Hongfu Li <lihongfu@kylinos.cn>
>>
>> range_contains_unmapped() accepts an explicit struct mm_struct *mm
>> argument, yet hardcodes current->mm inside VMA_ITERATOR(), ignoring
>> the passed address space.
>>
>> Its only caller do_mseal() currently passes current->mm, so the bug
>> does not manifest right now. However this mismatch between prototype
>> and implementation is a latent bug.
>>
>> Replace current->mm with the passed mm parameter to match the
>> function prototype.
>>
>> Fixes: 530e09096413 ("mm/mseal: simplify and rename VMA gap check")
> There's no point in a Fixes tag for something that's not a bug.
>
>> Signed-off-by: Hongfu Li <lihongfu@kylinos.cn>
>> ---
>> mm/mseal.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/mm/mseal.c b/mm/mseal.c
>> index 9781647483d1..8d82e50900ba 100644
>> --- a/mm/mseal.c
>> +++ b/mm/mseal.c
>> @@ -41,7 +41,7 @@ static bool range_contains_unmapped(struct mm_struct *mm,
>> {
>> struct vm_area_struct *vma;
>> unsigned long prev_end = start;
>> - VMA_ITERATOR(vmi, current->mm, start);
>> + VMA_ITERATOR(vmi, mm, start);
> We're never going to sensibly allow a remote mm here, and even suggesting so is
> problematic.
>
> Sorry but I think it's just easier if I send a broader cleanup patch to fix
> things up here more clearly.
Got it, thanks a lot for explaining the issue with remote mm. A unified
broad cleanup patch works better for this code path. I will withdraw my
patch and follow your series. Feel free to reach out if you need any
testing help later.
Best regards,
Hongfu
parent reply other threads:[~2026-07-17 1:35 UTC|newest]
Thread overview: expand[flat|nested] mbox.gz Atom feed
[parent not found: <alit0N1CBEllrD0U@lucifer>]
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