linux-kernel - Re: [PATCH 1/3] selftests/mm: virtual_address_range: Fix error when CommitLimit

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <eb3b0ebe-97b7-4504-aab0-3a008fd66c37@redhat.com>
Date: Thu, 9 Jan 2025 14:19:26 +0100
From: David Hildenbrand <david@...hat.com>
To: Thomas Weißschuh <thomas.weissschuh@...utronix.de>
Cc: Dev Jain <dev.jain@....com>, Andrew Morton <akpm@...ux-foundation.org>,
 Shuah Khan <shuah@...nel.org>, Thomas Gleixner <tglx@...utronix.de>,
 linux-mm@...ck.org, linux-kselftest@...r.kernel.org,
 linux-kernel@...r.kernel.org, stable@...r.kernel.org,
 Ryan Roberts <ryan.roberts@....com>
Subject: Re: [PATCH 1/3] selftests/mm: virtual_address_range: Fix error when
 CommitLimit < 1GiB

On 09.01.25 14:05, David Hildenbrand wrote:
>   >
>> That is clear. The issue would be to figure which chunks are valid to
>> unmap. If something critical like the executable file is unmapped,
>> the process crashes. But see below.
> 
> Ah, now I see what you mean. Yes, also the stack etc. will be
> problematic. So IIUC, you want to limit the munmap optimization only to
> the manually mmap()ed parts.
> 
>>
>>>> Is it fine to rely on CONFIG_ANON_VMA_NAME?
>>>> That would make it much easier to implement.
>>>
>>> Can you elaborate how you would do it?
>>
>> First set the VMA name after mmap():

I took a look at the implementation, and VMA merging seems to be able to 
merge such VMAs that share the same name (even when set separately).

So assuming you use the same name for all, that should indeed also work.

-- 
Cheers,

David / dhildenb