From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:38574) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZHCrj-0000K6-Qh for qemu-devel@nongnu.org; Mon, 20 Jul 2015 11:20:28 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZHCrf-0004sp-KN for qemu-devel@nongnu.org; Mon, 20 Jul 2015 11:20:27 -0400 Received: from mx1.redhat.com ([209.132.183.28]:33592) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZHCrf-0004sZ-DS for qemu-devel@nongnu.org; Mon, 20 Jul 2015 11:20:23 -0400 References: <1435765624-18404-1-git-send-email-armbru@redhat.com> <1435765624-18404-3-git-send-email-armbru@redhat.com> From: Eric Blake Message-ID: <55AD11B6.1070700@redhat.com> Date: Mon, 20 Jul 2015 09:20:22 -0600 MIME-Version: 1.0 In-Reply-To: <1435765624-18404-3-git-send-email-armbru@redhat.com> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="SGxDHu8odeE4M38w6Jxvp4KRMnhjOj27X" Subject: Re: [Qemu-devel] [PATCH for-2.4 2/2] qom: Fix invalid error check in property_get_str() List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Markus Armbruster , qemu-devel@nongnu.org Cc: Anthony Liguori , =?UTF-8?Q?Andreas_F=c3=a4rber?= This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --SGxDHu8odeE4M38w6Jxvp4KRMnhjOj27X Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable On 07/01/2015 09:47 AM, Markus Armbruster wrote: > When a function returns a null pointer on error and only on error, you > can do >=20 > if (!foo(foos, errp)) { > ... handle error ... > } >=20 > instead of the more cumbersome >=20 > Error *err =3D NULL; >=20 > if (!foo(foos, &err)) { > error_propagate(errp, err); > ... handle error ... > } >=20 > A StringProperty's getter, however, may return null on success! We > then fail to call visit_type_str(). >=20 > Screwed up in 6a146eb, v1.1. >=20 > Fails tests/qom-test in my current, heavily hacked QAPI branch. No > reproducer for master known (but I didn't look hard). >=20 > Cc: Andreas F=C3=A4rber > Cc: Anthony Liguori > Signed-off-by: Markus Armbruster > --- > qom/object.c | 12 ++++++++---- > 1 file changed, 8 insertions(+), 4 deletions(-) >=20 Reviewed-by: Eric Blake > diff --git a/qom/object.c b/qom/object.c > index 6173da8..4c4df55 100644 > --- a/qom/object.c > +++ b/qom/object.c > @@ -1591,14 +1591,18 @@ typedef struct StringProperty > static void property_get_str(Object *obj, Visitor *v, void *opaque, > const char *name, Error **errp) > { > + Error *err =3D NULL; > StringProperty *prop =3D opaque; > char *value; > =20 > - value =3D prop->get(obj, errp); > - if (value) { > - visit_type_str(v, &value, name, errp); > - g_free(value); > + value =3D prop->get(obj, &err); > + if (err) { > + error_propagate(errp, err); > + return; > } > + > + visit_type_str(v, &value, name, errp); > + g_free(value); > } > =20 > static void property_set_str(Object *obj, Visitor *v, void *opaque, >=20 --=20 Eric Blake eblake redhat com +1-919-301-3266 Libvirt virtualization library http://libvirt.org --SGxDHu8odeE4M38w6Jxvp4KRMnhjOj27X Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 Comment: Public key at http://people.redhat.com/eblake/eblake.gpg Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iQEcBAEBCAAGBQJVrRG2AAoJEKeha0olJ0Nqe4AH+wfo9l0it22sovP/sSA8lWjE XgPl8YoGFTkj8TK5ax6XkOA87LvWt2SMZraCZ7pIz114FdtitIk1UrdL333ilWEX mpojeRIXpedvxacTkYUjt0MtccBG4PVEiLBWIgGbInzHw3q5vMN9vB6aKgzXidZC 8grtem4PWlfBCYsqa8Di/TqII/ueZO5YyRWf0zk0mahX8CqEJVJwS/opXVHXzv7f ebUfo0ddeYlQqrt7vPkfcpQZg7hxekSqNYO3F+TQeog3Z6bFNfvgYW1Ybc5K1pGy 7la9hmZFiAhxwAkmJnHnXaW1BAqnQ+Iv7Dp4PtfhZTsabWH5hAkcV3AFJtsSCDQ= =zu2c -----END PGP SIGNATURE----- --SGxDHu8odeE4M38w6Jxvp4KRMnhjOj27X--