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Mon, 23 Mar 2020 14:12:00 +0000 (UTC) Received: from dresden.str.redhat.com (ovpn-114-242.ams2.redhat.com [10.36.114.242]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 9629710002A7; Mon, 23 Mar 2020 14:11:58 +0000 (UTC) Subject: Re: [PATCH 0/2] zero pointer after bdrv_unref_child To: Vladimir Sementsov-Ogievskiy , qemu-block@nongnu.org References: <20200316060631.30052-1-vsementsov@virtuozzo.com> From: Max Reitz Autocrypt: addr=mreitz@redhat.com; prefer-encrypt=mutual; keydata= mQENBFXOJlcBCADEyyhOTsoa/2ujoTRAJj4MKA21dkxxELVj3cuILpLTmtachWj7QW+TVG8U /PsMCFbpwsQR7oEy8eHHZwuGQsNpEtNC2G/L8Yka0BIBzv7dEgrPzIu+W3anZXQW4702+uES U29G8TP/NGfXRRHGlbBIH9KNUnOSUD2vRtpOLXkWsV5CN6vQFYgQfFvmp5ZpPeUe6xNplu8V mcTw8OSEDW/ZnxJc8TekCKZSpdzYoxfzjm7xGmZqB18VFwgJZlIibt1HE0EB4w5GsD7x5ekh awIe3RwoZgZDLQMdOitJ1tUc8aqaxvgA4tz6J6st8D8pS//m1gAoYJWGwwIVj1DjTYLtABEB AAG0HU1heCBSZWl0eiA8bXJlaXR6QHJlZGhhdC5jb20+iQFTBBMBCAA9AhsDBQkSzAMABQsJ CAcCBhUICQoLAgQWAgMBAh4BAheABQJVzie5FRhoa3A6Ly9rZXlzLmdudXBnLm5ldAAKCRD0 B9sAYdXPQDcIB/9uNkbYEex1rHKz3mr12uxYMwLOOFY9fstP5aoVJQ1nWQVB6m2cfKGdcRe1 2/nFaHSNAzT0NnKz2MjhZVmcrpyd2Gp2QyISCfb1FbT82GMtXFj1wiHmPb3CixYmWGQUUh+I AvUqsevLA+WihgBUyaJq/vuDVM1/K9Un+w+Tz5vpeMidlIsTYhcsMhn0L9wlCjoucljvbDy/ 8C9L2DUdgi3XTa0ORKeflUhdL4gucWoAMrKX2nmPjBMKLgU7WLBc8AtV+84b9OWFML6NEyo4 4cP7cM/07VlJK53pqNg5cHtnWwjHcbpGkQvx6RUx6F1My3y52vM24rNUA3+ligVEgPYBuQEN BFXOJlcBCADAmcVUNTWT6yLWQHvxZ0o47KCP8OcLqD+67T0RCe6d0LP8GsWtrJdeDIQk+T+F xO7DolQPS6iQ6Ak2/lJaPX8L0BkEAiMuLCKFU6Bn3lFOkrQeKp3u05wCSV1iKnhg0UPji9V2 W5eNfy8F4ZQHpeGUGy+liGXlxqkeRVhLyevUqfU0WgNqAJpfhHSGpBgihUupmyUg7lfUPeRM DzAN1pIqoFuxnN+BRHdAecpsLcbR8sQddXmDg9BpSKozO/JyBmaS1RlquI8HERQoe6EynJhd 64aICHDfj61rp+/0jTIcevxIIAzW70IadoS/y3DVIkuhncgDBvGbF3aBtjrJVP+5ABEBAAGJ ASUEGAEIAA8FAlXOJlcCGwwFCRLMAwAACgkQ9AfbAGHVz0CbFwf9F/PXxQR9i4N0iipISYjU sxVdjJOM2TMut+ZZcQ6NSMvhZ0ogQxJ+iEQ5OjnIputKvPVd5U7WRh+4lF1lB/NQGrGZQ1ic alkj6ocscQyFwfib+xIe9w8TG1CVGkII7+TbS5pXHRxZH1niaRpoi/hYtgzkuOPp35jJyqT/ /ELbqQTDAWcqtJhzxKLE/ugcOMK520dJDeb6x2xVES+S5LXby0D4juZlvUj+1fwZu+7Io5+B bkhSVPb/QdOVTpnz7zWNyNw+OONo1aBUKkhq2UIByYXgORPFnbfMY7QWHcjpBVw9MgC4tGeF R4bv+1nAMMxKmb5VvQCExr0eFhJUAHAhVg== Message-ID: Date: Mon, 23 Mar 2020 15:11:56 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.5.0 MIME-Version: 1.0 In-Reply-To: <20200316060631.30052-1-vsementsov@virtuozzo.com> X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="v7oVOJ5zz0VCAqRYPB3dZXX5tAi8iPSOP" X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 63.128.21.74 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: kwolf@redhat.com, den@openvz.org, qemu-devel@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --v7oVOJ5zz0VCAqRYPB3dZXX5tAi8iPSOP Content-Type: multipart/mixed; boundary="3LGuz0bAnEVzbQJ4I9oXd304RYmIzSrNA" --3LGuz0bAnEVzbQJ4I9oXd304RYmIzSrNA Content-Type: text/plain; charset=windows-1252 Content-Language: en-US Content-Transfer-Encoding: quoted-printable On 16.03.20 07:06, Vladimir Sementsov-Ogievskiy wrote: > Hi all! >=20 > I faced use-after-free of bs->backing pointer after bdrv_unref_child in > bdrv_set_backing_hd. >=20 > Fix it, and do similar thing for s->data_file in qcow2.c. >=20 > I'm not sure that this is the full fix. Is it safe to keep bs->backing > during bdrv_unref_child itself? Is it safe to keep bs->backing during > all-child-unref loop in bdrv_close? >=20 >=20 > Vladimir Sementsov-Ogievskiy (2): > block: bdrv_set_backing_bs: fix use-after-free > block/qcow2: zero data_file child after free Thanks, applied to my block branch: https://git.xanclic.moe/XanClic/qemu/commits/branch/block Max --3LGuz0bAnEVzbQJ4I9oXd304RYmIzSrNA-- --v7oVOJ5zz0VCAqRYPB3dZXX5tAi8iPSOP Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEEkb62CjDbPohX0Rgp9AfbAGHVz0AFAl54w6wACgkQ9AfbAGHV z0BZKwf+NH153r7tZScCe/W4AtPEX7f0t9AbTQeDqK8kQsLKYGCfm8yP8X4YddlR jqc0lW+qCLSrhDLnwXX5n6gxptcCO2U7jQ2h2bRK45OpKMT2EBq3LfgzBpy31eUZ KVF6JWjp8KwpA7tGmGEtD4TXL5BMeCHPPBD3FslYbhxy5lrLwBr6FuYg9ly2p1zs FyYniaKd3/8jsaVOq5E1d1KJ+oxj5MtQOsF5dFo1Rdz/6cQU+XMa1vQpHw/FaVQ5 HVUMg0m6OJR6rmyiOxiRsMpr/q7tA/To6DQULPnnEAFAVqZeLZSVHdK90w5AqKJt RFubPqlY2vsRDq3hO8+GCnNMFS8BLA== =2A2t -----END PGP SIGNATURE----- --v7oVOJ5zz0VCAqRYPB3dZXX5tAi8iPSOP--