linux-kernel - Re: dst_ifdown breaks infiniband?

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Mon, 19 Mar 2007 14:13:10 +0200
From:	"Michael S. Tsirkin" <mst@....mellanox.co.il>
To:	Alexey Kuznetsov <kuznet@....inr.ac.ru>
Cc:	"Michael S. Tsirkin" <mst@....mellanox.co.il>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	netdev@...r.kernel.org, general@...ts.openfabrics.org,
	Roland Dreier <rolandd@...co.com>,
	David Miller <davem@...emloft.net>
Subject: Re: dst_ifdown breaks infiniband?

> Quoting Alexey Kuznetsov <kuznet@....inr.ac.ru>:
> Subject: Re: dst_ifdown breaks infiniband?
> 
> Hello!
> 
> > If a device driver sets neigh_destructor in neigh_params, this could
> > get called after the device has been unregistered and the driver module
> > removed.
> 
> It is the same problem: if dst->neighbour holds neighbour, it should
> not hold device. parms->dev is not supposed to be used after
> neigh_parms_release(). F.e. set parms->dev to NULL to catch bad references.

Yes. I fixed that - simply checking that neighbour->dev is a
loopback device is sufficient to detect the fact that
the device is being unregistered.

> Do you search for a way to find real inifiniband device in
> ipoib_neigh_destructor()?

No, not anymore.

> I guess you will not be able.

I agree it's not possible.

> The problem is logical: if destructor needs device, neighbour entry
> _somehow_ have to hold reference to the device (via neigh->dev, neigh->parms,
> whatever). Hence, if we hold neighbour entry, unregister cannot be completed.
> Therefore, destructor cannot refer to device. Q.E.D. :-)
> 
> Seems, releasing dst->neighbour is inevitable.

infiniband sets parm->neigh_destructor, and I search for a way to prevent
this destructor from being called after the module has been unloaded.
Ideas?

-- 
MST
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/