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From: Oleg Nesterov <oleg@redhat.com>
To: Gregory Price <gourry@gourry.net>
Cc: Alistair Popple <apopple@nvidia.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Byungchul Park <byungchul@sk.com>,
	David Hildenbrand <david@kernel.org>,
	Joshua Hahn <joshua.hahnjy@gmail.com>,
	Matthew Brost <matthew.brost@intel.com>,
	Rakie Kim <rakie.kim@sk.com>,
	Ying Huang <ying.huang@linux.alibaba.com>,
	Zi Yan <ziy@nvidia.com>, Jann Horn <jannh@google.com>,
	Kees Cook <kees@kernel.org>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/4] mm/mempolicy: kernel_migrate_pages: simplify the usage of put_task_struct()
Date: Mon, 25 May 2026 10:27:06 +0200	[thread overview]
Message-ID: <ahQH2pLUc0Y4z4rU@redhat.com> (raw)
In-Reply-To: <ahOx-76r0JvTZHL_@gourry-fedora-PF4VCD3F>

On 05/24, Gregory Price wrote:
>
> On Sun, May 24, 2026 at 06:57:59PM +0200, Oleg Nesterov wrote:
> >
> >  	mm = get_task_mm(task);
> > -	put_task_struct(task);
> > -
>
> Hm, I was a little trigger-happy on that review, I just realized that
> this increases the scope in which there is a task reference held (i.e.
> we're now holding a reference across do_migrate_pages())
>
> I don't *think* that's an issue, but it might we worth looking at the
> changelog to see if this was done intentionally.

I did this to simplify the code and the next changes. We pin this task's
memory across do_migrate_pages(), so I think that delaying put_task_struct()
doesn't add too much.

But of course, this is not necessary, I can rework if you don't like it.

Thanks for review!

Oleg.



  reply	other threads:[~2026-05-25  8:27 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-05-24 16:57 [PATCH 0/4] mm/mempolicy: kernel_migrate_pages: fix race between security checks and suid exec Oleg Nesterov
2026-05-24 16:57 ` [PATCH 1/4] mm/mempolicy: kernel_migrate_pages: simplify the usage of put_task_struct() Oleg Nesterov
2026-05-25  2:18   ` Gregory Price
2026-05-25  2:20   ` Gregory Price
2026-05-25  8:27     ` Oleg Nesterov [this message]
2026-05-24 16:58 ` [PATCH 2/4] mm/mempolicy: kernel_migrate_pages: use find_get_task_by_vpid() Oleg Nesterov
2026-05-24 16:58 ` [PATCH 3/4] mm/mempolicy: kernel_migrate_pages: check ptrace_may_access() after nodes_and() Oleg Nesterov
2026-05-24 16:58 ` [PATCH 4/4] mm/mempolicy: kernel_migrate_pages: fix race between security checks and suid exec Oleg Nesterov
2026-05-24 19:29 ` [PATCH 0/4] " Oleg Nesterov

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