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From: Yafang Shao <laoar.shao@gmail.com>
To: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: akpm@linux-foundation.org, david@redhat.com, ziy@nvidia.com,
	 baolin.wang@linux.alibaba.com, Liam.Howlett@oracle.com,
	npache@redhat.com,  ryan.roberts@arm.com, dev.jain@arm.com,
	hannes@cmpxchg.org,  usamaarif642@gmail.com,
	gutierrez.asier@huawei-partners.com,  willy@infradead.org,
	ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org,
	 ameryhung@gmail.com, rientjes@google.com, corbet@lwn.net,
	bpf@vger.kernel.org,  linux-mm@kvack.org,
	linux-doc@vger.kernel.org
Subject: Re: [PATCH v6 mm-new 04/10] bpf: mark vma->vm_mm as trusted
Date: Thu, 28 Aug 2025 14:12:12 +0800	[thread overview]
Message-ID: <CALOAHbDxxN8CsGwAWQU4XRkG8NvU-chbiDv=oKW0mADSf1vaiQ@mail.gmail.com> (raw)
In-Reply-To: <bca7698c-7617-4584-afaa-4c3d2c971a79@lucifer.local>

On Wed, Aug 27, 2025 at 11:46 PM Lorenzo Stoakes
<lorenzo.stoakes@oracle.com> wrote:
>
> On Tue, Aug 26, 2025 at 03:19:42PM +0800, Yafang Shao wrote:
> > Every VMA must have an associated mm_struct, and it is safe to access
>
> Err this isn't true? Pretty sure special VMAs don't have that set.

I’m not aware of any VMA that doesn’t belong to an mm_struct. If there
is such a case, it would be helpful if you could point it out. In any
case, I’ll remove the VMA-related code in the next version since it’s
unnecessary.

>
> > outside of RCU. Thus, we can mark it as trusted. With this change, BPF
> > helpers can safely access vma->vm_mm to retrieve the associated task
> > from the VMA.
>
> On the basis of above don't think this is valid.
>

-- 
Regards
Yafang


  reply	other threads:[~2025-08-28  6:12 UTC|newest]

Thread overview: 61+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-08-26  7:19 [PATCH v6 mm-new 00/10] mm, bpf: BPF based THP order selection Yafang Shao
2025-08-26  7:19 ` [PATCH v6 mm-new 01/10] mm: thp: add support for " Yafang Shao
2025-08-27  2:57   ` kernel test robot
2025-08-27 11:39     ` Yafang Shao
2025-08-27 15:04       ` Lorenzo Stoakes
2025-08-27 15:03   ` Lorenzo Stoakes
2025-08-28  5:54     ` Yafang Shao
2025-08-28 10:50       ` Lorenzo Stoakes
2025-08-29  3:01         ` Yafang Shao
2025-08-29 10:42           ` Lorenzo Stoakes
2025-08-31  3:11             ` Yafang Shao
2025-09-01 11:39               ` Lorenzo Stoakes
2025-09-02  2:48                 ` Yafang Shao
2025-09-02  7:50                   ` Lorenzo Stoakes
2025-09-03  2:10                     ` Yafang Shao
2025-08-29  4:56   ` Barry Song
2025-08-29  5:36     ` Yafang Shao
2025-08-26  7:19 ` [PATCH v6 mm-new 02/10] mm: thp: add a new kfunc bpf_mm_get_mem_cgroup() Yafang Shao
2025-08-27 15:34   ` Lorenzo Stoakes
2025-08-27 20:50     ` Shakeel Butt
2025-08-28 10:40       ` Lorenzo Stoakes
2025-08-28 16:00         ` Shakeel Butt
2025-08-29 10:45           ` Lorenzo Stoakes
2025-08-28  6:57     ` Yafang Shao
2025-08-28 10:42       ` Lorenzo Stoakes
2025-08-29  3:09         ` Yafang Shao
2025-08-27 20:45   ` Shakeel Butt
2025-08-28  6:58     ` Yafang Shao
2025-08-26  7:19 ` [PATCH v6 mm-new 03/10] mm: thp: add a new kfunc bpf_mm_get_task() Yafang Shao
2025-08-27 15:42   ` Lorenzo Stoakes
2025-08-27 21:50     ` Andrii Nakryiko
2025-08-28  6:50       ` Yafang Shao
2025-08-28 10:51       ` Lorenzo Stoakes
2025-08-29  3:15         ` Yafang Shao
2025-08-29 10:42           ` Lorenzo Stoakes
2025-08-28  6:47     ` Yafang Shao
2025-08-29 10:43       ` Lorenzo Stoakes
2025-08-26  7:19 ` [PATCH v6 mm-new 04/10] bpf: mark vma->vm_mm as trusted Yafang Shao
2025-08-27 15:45   ` Lorenzo Stoakes
2025-08-28  6:12     ` Yafang Shao [this message]
2025-08-28 11:11       ` Lorenzo Stoakes
2025-08-29  3:05         ` Yafang Shao
2025-08-29 10:49           ` Lorenzo Stoakes
2025-08-31  3:16             ` Yafang Shao
2025-09-01 10:36               ` Lorenzo Stoakes
2025-08-26  7:19 ` [PATCH v6 mm-new 05/10] selftests/bpf: add a simple BPF based THP policy Yafang Shao
2025-08-26  7:19 ` [PATCH v6 mm-new 06/10] selftests/bpf: add test case for khugepaged fork Yafang Shao
2025-08-26  7:19 ` [PATCH v6 mm-new 07/10] selftests/bpf: add test case to update thp policy Yafang Shao
2025-08-26  7:19 ` [PATCH v6 mm-new 08/10] selftests/bpf: add test cases for invalid thp_adjust usage Yafang Shao
2025-08-26  7:19 ` [PATCH v6 mm-new 09/10] Documentation: add BPF-based THP adjustment documentation Yafang Shao
2025-08-26  7:19 ` [PATCH v6 mm-new 10/10] MAINTAINERS: add entry for BPF-based THP adjustment Yafang Shao
2025-08-27 15:47   ` Lorenzo Stoakes
2025-08-28  6:08     ` Yafang Shao
2025-08-26  7:42 ` [PATCH v6 mm-new 00/10] mm, bpf: BPF based THP order selection David Hildenbrand
2025-08-26  8:33   ` Lorenzo Stoakes
2025-08-26 12:06     ` Yafang Shao
2025-08-26  9:52   ` Usama Arif
2025-08-26 12:10     ` Yafang Shao
2025-08-26 12:03   ` Yafang Shao
2025-08-27 13:14 ` Lorenzo Stoakes
2025-08-28  2:58   ` Yafang Shao

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