From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dan Carpenter Subject: Re: [patch] [SCSI] scsi_transport_sas: check for allocation failure Date: Mon, 11 Mar 2013 16:10:32 +0300 Message-ID: <20130311131032.GO9189@mwanda> References: <20130308120215.GB18712@longonot.mountain> <513A2678.5000803@interlog.com> <1362783019.2370.45.camel@dabdike.int.hansenpartnership.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <1362783019.2370.45.camel@dabdike.int.hansenpartnership.com> Sender: linux-kernel-owner@vger.kernel.org To: James Bottomley Cc: dgilbert@interlog.com, linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org List-Id: linux-scsi@vger.kernel.org On Fri, Mar 08, 2013 at 10:50:19PM +0000, James Bottomley wrote: > On Fri, 2013-03-08 at 12:57 -0500, Douglas Gilbert wrote: > > On 13-03-08 07:02 AM, Dan Carpenter wrote: > > > Static checkers complain that this allocation isn't checked. We > > > should return zero if the allocation fails. > > > > > > Signed-off-by: Dan Carpenter > > > > > > diff --git a/drivers/scsi/scsi_transport_sas.c b/drivers/scsi/scsi_transport_sas.c > > > index 1b68142..a022997 100644 > > > --- a/drivers/scsi/scsi_transport_sas.c > > > +++ b/drivers/scsi/scsi_transport_sas.c > > > @@ -379,9 +379,12 @@ sas_tlr_supported(struct scsi_device *sdev) > > > { > > > const int vpd_len = 32; > > > struct sas_end_device *rdev = sas_sdev_to_rdev(sdev); > > > - char *buffer = kzalloc(vpd_len, GFP_KERNEL); > > > + char *buffer; > > > int ret = 0; > > > > > > + buffer = kzalloc(vpd_len, GFP_KERNEL); > > > + if (!buffer) > > > + goto out; > > > if (scsi_get_vpd_page(sdev, 0x90, buffer, vpd_len)) > > > goto out; > > > > > > > For 32 bytes, why not use the stack? > > Because the buffer is a DMA target. You can't DMA to stack because of > padding and cacheline issues. > I think stack data works here. scsi_execute() calls blk_rq_map_kern() which handles stack memory and alignment issues. regards, dan carpenter