Re: [PATCH] ib umem: bug: put pid back before return from error path

From: Kenneth Lee
Date: Wed Dec 28 2016 - 21:05:35 EST


Hi,

Sorry for the delay (I'd got some problem in my procmailrc file, and miss this
mail).

The new patch, with title "[PATCH] ib umem: bugfix: mixed put_pid()s in
ib_umem_get()", has been sent.

On Thu, Dec 22, 2016 at 10:00:57AM +0200, Mark Bloch wrote:
> Date: Thu, 22 Dec 2016 10:00:57 +0200
> From: Mark Bloch <markb@xxxxxxxxxxxx>
> To: Kenneth Lee <liguozhu@xxxxxxxxxxxxx>, dledford@xxxxxxxxxx,
> sean.hefty@xxxxxxxxx, hal.rosenstock@xxxxxxxxx
> CC: robin.murphy@xxxxxxx, jroedel@xxxxxxx, egtvedt@xxxxxxxxxxxx,
> vgupta@xxxxxxxxxxxx, dave.hansen@xxxxxxxxxxxxxxx, lstoakes@xxxxxxxxx,
> krzk@xxxxxxxxxx, sebott@xxxxxxxxxxxxxxxxxx, linux-rdma@xxxxxxxxxxxxxxx,
> linux-kernel@xxxxxxxxxxxxxxx
> Subject: Re: [PATCH] ib umem: bug: put pid back before return from error
> path
> User-Agent: Mozilla/5.0 (Windows NT 6.3; WOW64; rv:45.0) Gecko/20100101
> Thunderbird/45.5.1
> Message-ID: <e470fbab-a330-b9c4-f2b3-65fb45f24e0a@xxxxxxxxxxxx>
>
> Hi,
>
> You have two bugs here:
> 1) When using ODP, ib_umem_release() checks for umem->odp_data != NULL
> calls ib_umem_odp_release() and returns immediately without calling put_pid().
> This one isn't in the error path so the title doesn't fit.
>
> 2) In case the allocation failed, we return in -ENOMEM without calling put_pid().
>
> Can you please resend this with proper fixes line and a better description of what is going on.
>
> On 22/12/2016 09:11, Kenneth Lee wrote:
> > I catched this bug when reading the code. I'm sorry I have no hardware to test
> > it. But it is abviously a bug.
> >
> > Signed-off-by: Kenneth Lee <liguozhu@xxxxxxxxxxxxx>
> > ---
> > drivers/infiniband/core/umem.c | 2 ++
> > 1 file changed, 2 insertions(+)
> >
> > diff --git a/drivers/infiniband/core/umem.c b/drivers/infiniband/core/umem.c
> > index 1e62a5f..4609b92 100644
> > --- a/drivers/infiniband/core/umem.c
> > +++ b/drivers/infiniband/core/umem.c
> > @@ -134,6 +134,7 @@ struct ib_umem *ib_umem_get(struct ib_ucontext *context, unsigned long addr,
> > IB_ACCESS_REMOTE_ATOMIC | IB_ACCESS_MW_BIND));
> >
> > if (access & IB_ACCESS_ON_DEMAND) {
> > + put_pid(umem->pid);
> > ret = ib_umem_odp_get(context, umem);
> > if (ret) {
> > kfree(umem);
> > @@ -149,6 +150,7 @@ struct ib_umem *ib_umem_get(struct ib_ucontext *context, unsigned long addr,
> >
> > page_list = (struct page **) __get_free_page(GFP_KERNEL);
> > if (!page_list) {
> > + put_pid(umem->pid);
> > kfree(umem);
> > return ERR_PTR(-ENOMEM);
> > }
> >
>
> Mark.

--
-Kenneth(Hisilicon)