Re: Re: possible deadlock in cma_netdev_callback

[Jason Gunthorpe]

On Fri, Feb 28, 2020 at 01:05:53PM +0000, Bernard Metzler wrote:
> 
> >To: "Bernard Metzler" <BMT@xxxxxxxxxxxxxx>
> >From: "Jason Gunthorpe" <jgg@xxxxxxxx>
> >Date: 02/27/2020 05:46PM
> >Cc: "syzbot" <syzbot+55de90ab5f44172b0c90@xxxxxxxxxxxxxxxxxxxxxxxxx>,
> >chuck.lever@xxxxxxxxxx, dledford@xxxxxxxxxx, leon@xxxxxxxxxx,
> >linux-kernel@xxxxxxxxxxxxxxx, linux-rdma@xxxxxxxxxxxxxxx,
> >netdev@xxxxxxxxxxxxxxx, parav@xxxxxxxxxxxx,
> >syzkaller-bugs@xxxxxxxxxxxxxxxx, willy@xxxxxxxxxxxxx
> >Subject: [EXTERNAL] Re: possible deadlock in cma_netdev_callback
> >
> >On Thu, Feb 27, 2020 at 04:21:21PM +0000, Bernard Metzler wrote:
> >> 
> >> >To: "Bernard Metzler" <BMT@xxxxxxxxxxxxxx>
> >> >From: "Jason Gunthorpe" <jgg@xxxxxxxx>
> >> >Date: 02/27/2020 04:53PM
> >> >Cc: "syzbot"
> ><syzbot+55de90ab5f44172b0c90@xxxxxxxxxxxxxxxxxxxxxxxxx>,
> >> >chuck.lever@xxxxxxxxxx, dledford@xxxxxxxxxx, leon@xxxxxxxxxx,
> >> >linux-kernel@xxxxxxxxxxxxxxx, linux-rdma@xxxxxxxxxxxxxxx,
> >> >netdev@xxxxxxxxxxxxxxx, parav@xxxxxxxxxxxx,
> >> >syzkaller-bugs@xxxxxxxxxxxxxxxx, willy@xxxxxxxxxxxxx
> >> >Subject: [EXTERNAL] Re: possible deadlock in cma_netdev_callback
> >> >
> >> >On Thu, Feb 27, 2020 at 10:11:13AM +0000, Bernard Metzler wrote:
> >> >
> >> >> Thanks for letting me know! Hmm, we cannot use RCU locks since
> >> >> we potentially sleep. One solution would be to create a list
> >> >> of matching interfaces while under lock, unlock and use that
> >> >> list for calling siw_listen_address() (which may sleep),
> >> >> right...?
> >> >
> >> >Why do you need to iterate over addresses anyhow? Shouldn't the
> >> >listen
> >> >just be done with the address the user gave and a BIND DEVICE to
> >the
> >> >device siw is connected to?
> >> 
> >> The user may give a wildcard local address, so we'd have
> >> to bind to all addresses of that device...
> >
> >AFAIK a wild card bind using BIND DEVICE works just fine?
> >
> >Jason
> >
> Thanks Jason, absolutely! And it makes things so easy...

Probably check to confirm, it just my memory..

Jason