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From: Peter Xu <peterx@redhat.com>
To: Suren Baghdasaryan <surenb@google.com>
Cc: akpm@linux-foundation.org, lokeshgidra@google.com,
	aarcange@redhat.com, 21cnbao@gmail.com, v-songbaohua@oppo.com,
	david@redhat.com, willy@infradead.org, Liam.Howlett@oracle.com,
	lorenzo.stoakes@oracle.com, hughd@google.com, jannh@google.com,
	kaleshsingh@google.com, linux-mm@kvack.org,
	linux-kernel@vger.kernel.org, stable@vger.kernel.org
Subject: Re: [PATCH 2/2] userfaultfd: fix PTE unmapping stack-allocated PTE copies
Date: Wed, 26 Feb 2025 15:43:42 -0500	[thread overview]
Message-ID: <Z798_nEvv6YVZntx@x1.local> (raw)
In-Reply-To: <20250226185510.2732648-3-surenb@google.com>

On Wed, Feb 26, 2025 at 10:55:09AM -0800, Suren Baghdasaryan wrote:
> Current implementation of move_pages_pte() copies source and destination
> PTEs in order to detect concurrent changes to PTEs involved in the move.
> However these copies are also used to unmap the PTEs, which will fail if
> CONFIG_HIGHPTE is enabled because the copies are allocated on the stack.
> Fix this by using the actual PTEs which were kmap()ed.
> 
> Fixes: adef440691ba ("userfaultfd: UFFDIO_MOVE uABI")
> Reported-by: Peter Xu <peterx@redhat.com>
> Signed-off-by: Suren Baghdasaryan <surenb@google.com>
> Cc: stable@vger.kernel.org

Reviewed-by: Peter Xu <peterx@redhat.com>

-- 
Peter Xu



      reply	other threads:[~2025-02-26 20:43 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-02-26 18:55 [PATCH 0/2] move_pages_pte() fixes Suren Baghdasaryan
2025-02-26 18:55 ` [PATCH 1/2] userfaultfd: do not block on locking a large folio with raised refcount Suren Baghdasaryan
2025-02-26 20:23   ` Liam R. Howlett
2025-02-26 18:55 ` [PATCH 2/2] userfaultfd: fix PTE unmapping stack-allocated PTE copies Suren Baghdasaryan
2025-02-26 20:43   ` Peter Xu [this message]

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