Re: [PATCH for-next 3/9] RDMA/hns: Add return statement when kzalloc return NULL in hns_roce_v1_recreate_lp_qp

[Leon Romanovsky]

On Thu, Sep 28, 2017 at 07:56:59PM +0800, Wei Hu (Xavier) wrote:
>
>
> On 2017/9/28 17:13, Leon Romanovsky wrote:
> > On Thu, Sep 28, 2017 at 12:57:28PM +0800, Wei Hu (Xavier) wrote:
> > > From: Lijun Ou <oulijun@xxxxxxxxxx>
> > >
> > > When lp_qp_work is NULL, it should be returned ENOMEM. This patch
> > > mainly fixes it.
> > >
> > > Ihis patch fixes the smatch error as below:
> > > drivers/infiniband/hw/hns/hns_roce_hw_v1.c:918 hns_roce_v1_recreate_lp_qp()
> > > error: potential null dereference 'lp_qp_work'.  (kzalloc returns null)
> > >
> > > Signed-off-by: Lijun Ou <oulijun@xxxxxxxxxx>
> > > Signed-off-by: Wei Hu (Xavier) <xavier.huwei@xxxxxxxxxx>
> > > Signed-off-by: Shaobo Xu <xushaobo2@xxxxxxxxxx>
> > > ---
> > >   drivers/infiniband/hw/hns/hns_roce_hw_v1.c | 2 ++
> > >   1 file changed, 2 insertions(+)
> > >
> > > diff --git a/drivers/infiniband/hw/hns/hns_roce_hw_v1.c b/drivers/infiniband/hw/hns/hns_roce_hw_v1.c
> > > index 95f5c88..1071fa2 100644
> > > --- a/drivers/infiniband/hw/hns/hns_roce_hw_v1.c
> > > +++ b/drivers/infiniband/hw/hns/hns_roce_hw_v1.c
> > > @@ -912,6 +912,8 @@ static int hns_roce_v1_recreate_lp_qp(struct hns_roce_dev *hr_dev)
> > >
> > >   	lp_qp_work = kzalloc(sizeof(struct hns_roce_recreate_lp_qp_work),
> > >   			     GFP_KERNEL);
> > > +	if (!lp_qp_work)
> > > +		return -ENOMEM;
> > >
> > You will treat this error in the same was as you will treat timeout,
> > which is wrong.
> Thanks,  Leon
> We will send v2 to fix the compatible warn info.

No, you missed the point.
From the code flow below the behavior of hns_roce_v1_recreate_lp_qp
for ENOMEM and ETIMEOUT returns will be the same and it is wrong.

For the ETIMEOUT, you can continue, for ENOMEM, you should properly
unfold the whole flow.

Thanks


> > 1656          */
> > 1657         if (hr_dev->hw->dereg_mr && hns_roce_v1_recreate_lp_qp(hr_dev))
> > 1658                 dev_warn(&hr_dev->pdev->dev, "recreate lp qp timeout!\n");
> > 1659
> > 1660         p = (u32 *)(&addr[0]);
> >
> >
> > >   	INIT_WORK(&(lp_qp_work->work), hns_roce_v1_recreate_lp_qp_work_fn);
> > >
> > > --
> > > 1.9.1
> > >
> > > --
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>
>
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