Message-ID: <643097f2-f29e-313b-cfb1-4095ae641448@collabora.com>
Date:   Fri, 17 Feb 2023 15:40:51 +0500
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Cc:     Muhammad Usama Anjum <usama.anjum@collabora.com>,
        David Hildenbrand <david@redhat.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        kernel@collabora.com, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH v4 2/2] mm/userfaultfd: add VM_WARN_ONCE()
Content-Language: en-US
To:     Peter Xu <peterx@redhat.com>
References: <20230216091656.2045471-1-usama.anjum@collabora.com>
 <20230216091656.2045471-2-usama.anjum@collabora.com>
 <4d29a9ec-027d-06b9-8543-87d386e58c94@redhat.com>
 <c239e126-9b75-9a81-6142-a8e518e769e2@collabora.com> <Y+6Rc8RUiv7xAlKH@x1n>
From:   Muhammad Usama Anjum <usama.anjum@collabora.com>
In-Reply-To: <Y+6Rc8RUiv7xAlKH@x1n>
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On 2/17/23 1:26 AM, Peter Xu wrote:
> On Thu, Feb 16, 2023 at 02:48:51PM +0500, Muhammad Usama Anjum wrote:
>> On 2/16/23 2:24 PM, David Hildenbrand wrote:
>>> On 16.02.23 10:16, Muhammad Usama Anjum wrote:
>>>> Add VM_WARN_ONCE() to uffd_wp_range() to detect range (start, len) abuse.
>>>>
>>>> Signed-off-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
>>>> ---
>>>>   mm/userfaultfd.c | 2 ++
>>>>   1 file changed, 2 insertions(+)
>>>>
>>>> diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c
>>>> index 77c5839e591c..d89ed44d2668 100644
>>>> --- a/mm/userfaultfd.c
>>>> +++ b/mm/userfaultfd.c
>>>> @@ -717,6 +717,8 @@ long uffd_wp_range(struct mm_struct *dst_mm, struct
>>>> vm_area_struct *dst_vma,
>>>>       struct mmu_gather tlb;
>>>>       long ret;
>>>>   +    VM_WARN_ONCE(start < dst_vma->vm_start || start + len >
>>>> dst_vma->vm_end,
>>>> +             "The address range exceeds VMA boundary.\n");
>>>
>>> VM_WARN_ON_ONCE is sufficient (sorry for spelling out the wrong variant
>>> earlier).
>> Will do in the next version. Thanks.
> 
> Shall we just squash the two patches?
Will squash in next version.

> 

-- 
BR,
Muhammad Usama Anjum