From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:40741) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1degaX-0003rD-Pd for qemu-devel@nongnu.org; Mon, 07 Aug 2017 07:52:54 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1degaS-0008M5-Tu for qemu-devel@nongnu.org; Mon, 07 Aug 2017 07:52:49 -0400 References: <20170804151440.320927-1-vsementsov@virtuozzo.com> <20170804151440.320927-7-vsementsov@virtuozzo.com> From: Eric Blake Message-ID: <4dc2dde8-2177-3d1c-c168-f98d826922b5@redhat.com> Date: Mon, 7 Aug 2017 06:52:30 -0500 MIME-Version: 1.0 In-Reply-To: <20170804151440.320927-7-vsementsov@virtuozzo.com> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="PR8CJqMS7R3vp0UgXQBsn3huAmJgffWHD" Subject: Re: [Qemu-devel] [PATCH 06/17] block/nbd-client: fix nbd_read_reply_entry List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Vladimir Sementsov-Ogievskiy , qemu-block@nongnu.org, qemu-devel@nongnu.org Cc: mreitz@redhat.com, kwolf@redhat.com, pbonzini@redhat.com, den@openvz.org This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --PR8CJqMS7R3vp0UgXQBsn3huAmJgffWHD From: Eric Blake To: Vladimir Sementsov-Ogievskiy , qemu-block@nongnu.org, qemu-devel@nongnu.org Cc: mreitz@redhat.com, kwolf@redhat.com, pbonzini@redhat.com, den@openvz.org Message-ID: <4dc2dde8-2177-3d1c-c168-f98d826922b5@redhat.com> Subject: Re: [PATCH 06/17] block/nbd-client: fix nbd_read_reply_entry References: <20170804151440.320927-1-vsementsov@virtuozzo.com> <20170804151440.320927-7-vsementsov@virtuozzo.com> In-Reply-To: <20170804151440.320927-7-vsementsov@virtuozzo.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable On 08/04/2017 10:14 AM, Vladimir Sementsov-Ogievskiy wrote: > Set reply.handle to 0 on error path to prevent normal path of > nbd_co_receive_reply. >=20 > Signed-off-by: Vladimir Sementsov-Ogievskiy > --- > block/nbd-client.c | 1 + > 1 file changed, 1 insertion(+) Can you document a case where not fixing this would be an observable bug (even if it requires using gdb and single-stepping between client and server to make what is otherwise a racy situation easy to see)? I'm trying to figure out if this is 2.10 material. >=20 > diff --git a/block/nbd-client.c b/block/nbd-client.c > index dc19894a7c..0c88d84de6 100644 > --- a/block/nbd-client.c > +++ b/block/nbd-client.c > @@ -107,6 +107,7 @@ static coroutine_fn void nbd_read_reply_entry(void = *opaque) > qemu_coroutine_yield(); > } > =20 > + s->reply.handle =3D 0; > nbd_recv_coroutines_enter_all(s); > s->read_reply_co =3D NULL; > } >=20 --=20 Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3266 Virtualization: qemu.org | libvirt.org --PR8CJqMS7R3vp0UgXQBsn3huAmJgffWHD Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Comment: Public key at http://people.redhat.com/eblake/eblake.gpg Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iQEzBAEBCAAdFiEEccLMIrHEYCkn0vOqp6FrSiUnQ2oFAlmIVH4ACgkQp6FrSiUn Q2p1Kgf/TjCqZZJ4QSSpNWfyS0id/GB/khoztQglP3aO07Rk3sM+4qPyJq39o7Pf KB79u5qsxJ4I5dkVijA5qtBf2Hg+tAHNm6AQNuVrwt+g53G1Zxui//TdNUEtRjf8 8xgQrCSeJS+B4mWBlUt6EPgFZZc9hY60IOTLDjdS3HjdS+cq5WXYsYvRNRK56tH7 Dq773GSWxC3qZ1O9JnPfvOUBKP8pKlUcee+Ml3tQuMaQ4K2XxNH8Ucd+kEwLpo3v X8/j4jbIs9zPCfOtdpVnUWaRHOaP7OxapiY91u5g8QXVKVnfy7KOZv6DITh+LVd0 bufj0oU+jJ0Jy1g7zHPWUyHj6+rN4g== =yfNa -----END PGP SIGNATURE----- --PR8CJqMS7R3vp0UgXQBsn3huAmJgffWHD--