[PATCH v2] vhost: fix unchecked return value

[Hu, Jiayu]

Hi Maxime,

> -----Original Message-----
> From: Maxime Coquelin <maxime.coquelin at redhat.com>
> Sent: Thursday, June 30, 2022 5:57 PM
> To: Hu, Jiayu <jiayu.hu at intel.com>; dev at dpdk.org
> Cc: Xia, Chenbo <chenbo.xia at intel.com>; stable at dpdk.org; David Marchand
> <david.marchand at redhat.com>
> Subject: Re: [PATCH v2] vhost: fix unchecked return value
> 
> 
> 
> On 6/29/22 11:07, Jiayu Hu wrote:
> > This patch checks the return value of rte_dma_info_get() called in
> > rte_vhost_async_dma_configure().
> >
> > Coverity issue: 379066
> > Fixes: 53d3f4778c1d ("vhost: integrate dmadev in asynchronous
> > data-path")
> > Cc: stable at dpdk.org
> >
> > Signed-off-by: Jiayu Hu <jiayu.hu at intel.com>
> > Reviewed-by: Chenbo Xia <chenbo.xia at intel.com>
> > ---
> > v2:
> > - add cc stable tag
> > ---
> >   lib/vhost/vhost.c | 6 +++++-
> >   1 file changed, 5 insertions(+), 1 deletion(-)
> >
> > diff --git a/lib/vhost/vhost.c b/lib/vhost/vhost.c index
> > b14521e4d1..70c04c036e 100644
> > --- a/lib/vhost/vhost.c
> > +++ b/lib/vhost/vhost.c
> > @@ -1868,7 +1868,11 @@ rte_vhost_async_dma_configure(int16_t
> dma_id, uint16_t vchan_id)
> >   		return -1;
> >   	}
> >
> > -	rte_dma_info_get(dma_id, &info);
> > +	if (rte_dma_info_get(dma_id, &info) != 0) {
> > +		VHOST_LOG_CONFIG(ERR, "Fail to get DMA %d
> information.\n", dma_id);
> > +		return -1;
> > +	}
> > +
> >   	if (vchan_id >= info.max_vchans) {
> >   		VHOST_LOG_CONFIG(ERR, "Invalid DMA %d vChannel %u.\n",
> dma_id, vchan_id);
> >   		return -1;
> 
> The patch itself looks good, but rte_vhost_async_dma_configure() should be
> protected by a lock, as concurrent calls of this function would lead to
> undefined behavior.

This function is expected to be called only once. Is there any use case to cause it
called concurrently?

Thanks,
Jiayu
> 
> Can you cook something?
> 
> David, is that the issue you mentioned me this week or was it another one?
> 
> Thanks,
> Maxime