From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id F1C341494C3; Tue, 23 Apr 2024 21:44:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713908666; cv=none; b=KgcNZTZ94jqtRRLDojA4/Slt86jjzJ/S8nsL5FLKDqcEBzJl66voVStgZYJRVg3KyAUgNI+Of4SSwfoP9vSeSTYHLg4Ed2J//Uhbcwnv4XNMfxOCJhBJj1Mvawq2lmVybzP5AveZ/TosA4zf3aA2h5jVmgsZWDfxhNPa8Ho7QCo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713908666; c=relaxed/simple; bh=C6Bz1pyJg1sKNcsZnlfP919m0MVianviUb4OKEHcqyM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Txe1j8IJT+3JTbXs+Yn04tHK4qAaZwu+NQBt2SUxIOkTVhY9dRLgS551iL7o43hepo84aVUHba4SfuT9+TermvKF6BcGBbgpRG6yZwK6sMadIGd/S/tHck6B9KQuFIDu0s+FwsLGGZg+EqJifoHw2jd74fp2Qpn+gNePj1/ACkw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=aJ6gOGI9; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="aJ6gOGI9" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C3D65C3277B; Tue, 23 Apr 2024 21:44:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1713908665; bh=C6Bz1pyJg1sKNcsZnlfP919m0MVianviUb4OKEHcqyM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=aJ6gOGI9RDUCl54/4XJmzyUSNmIF5oqDRWjJ2KB/QTLnojnj16IOCqlM3F9lcMTm8 8Qa9pvAtXEL4mOvMKFYPxiyCtO6aKXozNfHKOcxs4YZl6gh9/2Ad4l6YldEfG2jcLC I9lYcjzhhEWrISnh/+IQu1PM+RrUTQE4FpOTGXWU= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Peter Xu , syzbot+b07c8ac8eee3d4d8440f@syzkaller.appspotmail.com, David Hildenbrand , Axel Rasmussen , Andrew Morton Subject: [PATCH 6.6 136/158] mm/userfaultfd: allow hugetlb change protection upon poison entry Date: Tue, 23 Apr 2024 14:39:33 -0700 Message-ID: <20240423213900.122009374@linuxfoundation.org> X-Mailer: git-send-email 2.44.0 In-Reply-To: <20240423213855.696477232@linuxfoundation.org> References: <20240423213855.696477232@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Peter Xu commit c5977c95dff182d6ee06f4d6f60bcb0284912969 upstream. After UFFDIO_POISON, there can be two kinds of hugetlb pte markers, either the POISON one or UFFD_WP one. Allow change protection to run on a poisoned marker just like !hugetlb cases, ignoring the marker irrelevant of the permission. Here the two bits are mutual exclusive. For example, when install a poisoned entry it must not be UFFD_WP already (by checking pte_none() before such install). And it also means if UFFD_WP is set there must have no POISON bit set. It makes sense because UFFD_WP is a bit to reflect permission, and permissions do not apply if the pte is poisoned and destined to sigbus. So here we simply check uffd_wp bit set first, do nothing otherwise. Attach the Fixes to UFFDIO_POISON work, as before that it should not be possible to have poison entry for hugetlb (e.g., hugetlb doesn't do swap, so no chance of swapin errors). Link: https://lkml.kernel.org/r/20240405231920.1772199-1-peterx@redhat.com Link: https://lore.kernel.org/r/000000000000920d5e0615602dd1@google.com Fixes: fc71884a5f59 ("mm: userfaultfd: add new UFFDIO_POISON ioctl") Signed-off-by: Peter Xu Reported-by: syzbot+b07c8ac8eee3d4d8440f@syzkaller.appspotmail.com Reviewed-by: David Hildenbrand Reviewed-by: Axel Rasmussen Cc: [6.6+] Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman --- mm/hugetlb.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -6653,9 +6653,13 @@ long hugetlb_change_protection(struct vm if (!pte_same(pte, newpte)) set_huge_pte_at(mm, address, ptep, newpte, psize); } else if (unlikely(is_pte_marker(pte))) { - /* No other markers apply for now. */ - WARN_ON_ONCE(!pte_marker_uffd_wp(pte)); - if (uffd_wp_resolve) + /* + * Do nothing on a poison marker; page is + * corrupted, permissons do not apply. Here + * pte_marker_uffd_wp()==true implies !poison + * because they're mutual exclusive. + */ + if (pte_marker_uffd_wp(pte) && uffd_wp_resolve) /* Safe to modify directly (non-present->none). */ huge_pte_clear(mm, address, ptep, psize); } else if (!huge_pte_none(pte)) {