From mboxrd@z Thu Jan 1 00:00:00 1970 From: Cornelia Huck Subject: Re: [PATCH 3/4] vfio: ccw: set ccw->cda to NULL defensively Date: Mon, 26 Mar 2018 15:47:53 +0200 Message-ID: <20180326154753.327503ba.cohuck@redhat.com> References: <20180321020822.86255-1-bjsdjshi@linux.vnet.ibm.com> <20180321020822.86255-4-bjsdjshi@linux.vnet.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org, kvm@vger.kernel.org, borntraeger@de.ibm.com, pasic@linux.vnet.ibm.com, pmorel@linux.vnet.ibm.com To: Dong Jia Shi Return-path: In-Reply-To: <20180321020822.86255-4-bjsdjshi@linux.vnet.ibm.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org On Wed, 21 Mar 2018 03:08:21 +0100 Dong Jia Shi wrote: > Let's avoid free on ccw->cda that points to a guest address > or a already freed memory area by setting it to NULL if memory > allocation didn't happen or failed. Does not hurt, I guess. > > Signed-off-by: Dong Jia Shi > --- > drivers/s390/cio/vfio_ccw_cp.c | 28 +++++++++++++++++++--------- > 1 file changed, 19 insertions(+), 9 deletions(-) > > diff --git a/drivers/s390/cio/vfio_ccw_cp.c b/drivers/s390/cio/vfio_ccw_cp.c > index 3abc9770910a..5958c35ab343 100644 > --- a/drivers/s390/cio/vfio_ccw_cp.c > +++ b/drivers/s390/cio/vfio_ccw_cp.c > @@ -491,7 +491,7 @@ static int ccwchain_fetch_direct(struct ccwchain *chain, > struct ccw1 *ccw; > struct pfn_array_table *pat; > unsigned long *idaws; > - int idaw_nr; > + int idaw_nr, ret; > > ccw = chain->ch_ccw + idx; > > @@ -511,18 +511,20 @@ static int ccwchain_fetch_direct(struct ccwchain *chain, > * needed when translating a direct ccw to a idal ccw. > */ > pat = chain->ch_pat + idx; > - if (pfn_array_table_init(pat, 1)) > - return -ENOMEM; > - idaw_nr = pfn_array_alloc_pin(pat->pat_pa, cp->mdev, > + ret = pfn_array_table_init(pat, 1); > + if (ret) > + goto out_init; > + > + idaw_nr = ret = pfn_array_alloc_pin(pat->pat_pa, cp->mdev, Ugh, I don't like setting both at the same time... only set idaw_nr for ret > 0? (personal preference) > ccw->cda, ccw->count); > - if (idaw_nr < 0) > - return idaw_nr; > + if (ret < 0) > + goto out_init;