From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793832854; b=sd/Ltasc3oNnpDT/eaT/HAyOAS+gfmHIiA68BWuIKxQdPyZlPoJjAb6bUXO4BLc9VMaL aP2Hp02yofHw3VgllLqA/yMNG2+XjkHLj0Dcw9cKihirh52YMmdHqD0WN+UTsB//+asZY AibS0sA4ROAvZFJ8+X3zHtgfVDsMUVb8oIp+um444RgOzykTHMItz2Fo+SvmDK77GCAJN j6vNAo+MqxCUGKfverK4m+epUo/1UHNj2swpmZbuetXVoqDjC0VFy/pteSybvSjqJmVuu 4+qHjc6/JyhIR3dmE1br917zbdekGHhDJdG+KBB1ulY+qQEWVCkGGpyALldkKHxDQ9Q== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793832854; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:MIME-Version:Content-Transfer-Encoding; bh=AJxJW64brnfqY5WaIVwBzjPhZWOifxw1Ma+QZJjvFYs=; b=KHXkJx8T7h9JHTt5npjlqlmPVPyfG7lvjdbBMY+NQvhQB2H3djIxYJ5VEdQQgnvkCrN3 y0Oy2y1xVa4vKD0pu8cQFmJvJ1VsNpH3aUnRFrvts5YTaDLYaBX71dQQ8r9KHH4VT4M85 NzTtSTQy8HXQAsJYuXM/jYv4dypuOX6NmH4JvHrTEnsjYHsb5IOqT0kh2Hn1vH7MC5Z69 7oqc41rQ0Mns8lAKxuKV8OnHQ3FjrxypbhR8tsxi7gRpDYUFhqYI4gUfPxCApX5aY9eC0 c4/B3AHOXpdyjtbL6AOcHfoIaEMcEFFVN7i9GSwMjVP75wyuCpRHTbbwtw0esCnMnKg== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=I7gXEs4H; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9F94E606A328 for ; Wed, 4 Nov 2026 22:54:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=I7gXEs4H Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7C5091F000C1; Wed, 4 Nov 2026 22:54:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793832854; bh=AJxJW64brnfqY5WaIVwBzjPhZWOifxw1Ma+QZJjvFYs=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=I7gXEs4HICnhDKUEkgp0Vshz6QWWwsxLdgquopwIOI6oJ22zKLg8MPZP9fbJRZ5bR FUw8Nh/jncmPvFJ6sjIxFKlTuRyNNAuwvNeUQoFb1VN7dc69VoIvMYNk1oufx577Ma tkDLawiiKh/B0LBwvQjHc5yEsMCwlGKsemeBujaD22TAv17XrFkE8kwiPB9UJpMUPQ d4d4cy3kmYxLMC3wzOmyCT/lXGspew7UcpdD72l4h2QKYQmsAA3svQFUclcY1/vlYm YVTQqgMtRwwM7SJ23K59+Rlnji4K89zh5+bPcvty+eU2U6+ssmMHQTg+BQxPPjkW7z xUUv77Y9wJfPQ== From: Sasha Levin To: stable@vger.kernel.org Cc: "David Hildenbrand (Arm)" , Andrew Morton , "Lorenzo Stoakes (ARM)" , Muchun Song , Lance Yang , "Liam R. Howlett" , Vlastimil Babka , Jann Horn , Pedro Falcato , Oscar Salvador , Miaohe Lin , Naoya Horiguchi , Adam Litke , Mel Gorman , Rik van Riel , Peter Xu , Kiryl Shutsemau , Mike Rapoport , Josef Bacik , Sasha Levin Subject: [PATCH 5.10.y] mm/hugetlb: fix use-after-free in hugetlb_mfill_atomic_pte() Date: Wed, 4 Nov 2026 17:54:11 -0500 Message-ID: <20261104225336.846864-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <2026110447-friend-unmanaged-5374@gregkh> References: <2026110447-friend-unmanaged-5374@gregkh> X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: "David Hildenbrand (Arm)" [ Upstream commit d8a9cd7fd2fb01211430c933932da58839b8ca65 ] Let's fix another instance where we use a folio after dropping the PTL, where someone else could e.g., MADV_DONTNEED it once we drop the PTL, making us trigger a use-after-free on the folio. Link: https://lore.kernel.org/20261015-urgent_fixes-v1-3-42796911043b@kernel.org Fixes: cb6acd01e2e4 ("hugetlbfs: fix races and page leaks during migration") Fixes: 1c9e8def43a3 ("userfaultfd: hugetlbfs: add UFFDIO_COPY support for shared mappings") Signed-off-by: David Hildenbrand (Arm) Signed-off-by: Andrew Morton Reported-by: Lorenzo Stoakes (ARM) Reviewed-by: Lorenzo Stoakes (ARM) Acked-by: Muchun Song Reviewed-by: Lance Yang Cc: Liam R. Howlett Cc: Vlastimil Babka Cc: Jann Horn Cc: Pedro Falcato Cc: Oscar Salvador Cc: Miaohe Lin Cc: Naoya Horiguchi Cc: Adam Litke Cc: Mel Gorman Cc: Rik van Riel Cc: Peter Xu Cc: Kiryl Shutsemau Cc: Mike Rapoport Cc: Josef Bacik Cc: [ sashal: Adapted folio-based hugetlb_mfill_atomic_pte() logic to page-based hugetlb_mcopy_atomic_pte() without continue support. ] Signed-off-by: Sasha Levin --- mm/hugetlb.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/mm/hugetlb.c b/mm/hugetlb.c index b23c8b2699b58..da47b6d218e01 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -4806,10 +4806,15 @@ int hugetlb_mcopy_atomic_pte(struct mm_struct *dst_mm, /* No need to invalidate - it was non-present before */ update_mmu_cache(dst_vma, dst_addr, dst_pte); - spin_unlock(ptl); set_page_huge_active(page); if (vm_shared) unlock_page(page); + + /* + * Hold the PTL until we're done with the page: the page table owns the + * page reference now. + */ + spin_unlock(ptl); ret = 0; out: return ret; -- 2.53.0