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Date: Tue, 26 May 2026 13:24:23 -0700
From: Andrew Morton <akpm@linux-foundation.org>
To: Oleg Nesterov <oleg@redhat.com>
Cc: Alistair Popple <apopple@nvidia.com>, Byungchul Park <byungchul@sk.com>,
 David Hildenbrand <david@kernel.org>, Gregory Price <gourry@gourry.net>,
 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] mm/migrate: find_mm_struct: fix race between security
 checks and suid exec
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On Tue, 26 May 2026 16:42:11 +0200 Oleg Nesterov <oleg@redhat.com> wrote:

> The target task can execute a setuid binary between ptrace_may_access()
> and get_task_mm(). Protect this critical section with exec_update_lock.
> 
> I don't think cpuset_mems_allowed(task) should be called under
> exec_update_lock, but this patch just tries to add the minimal fix.
> 
> Perhaps we can later add a common helper which can be used by
> find_mm_struct() and kernel_migrate_pages().
> 

Do you think we should backport this into earlier kernels?