| Submitter | Amerigo Wang |
|---|---|
| Date | Jan. 28, 2013, 1:55 a.m. |
| Message ID | <1359338121-10897-2-git-send-email-amwang@redhat.com> |
| Download | mbox | patch |
| Permalink | /patch/216100/ |
| State | Accepted |
| Delegated to: | David Miller |
| Headers | show |
Comments
From: Cong Wang <amwang@redhat.com> Date: Mon, 28 Jan 2013 09:55:21 +0800 > From: Cong Wang <amwang@redhat.com> > > This will allow us to setup netconsole in a different namespace > rather than where init_net is. > > Cc: Eric W. Biederman <ebiederm@xmission.com> > Cc: David S. Miller <davem@davemloft.net> > Signed-off-by: Cong Wang <amwang@redhat.com> Applied but: > + if (np->dev_name) { > + struct net *net = current->nsproxy->net_ns; > + ndev = __dev_get_by_name(net, np->dev_name); > + } I wonder if you should be using task_nsproxy() here. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
David Miller <davem@davemloft.net> writes: > From: Cong Wang <amwang@redhat.com> > Date: Mon, 28 Jan 2013 09:55:21 +0800 > >> From: Cong Wang <amwang@redhat.com> >> >> This will allow us to setup netconsole in a different namespace >> rather than where init_net is. >> >> Cc: Eric W. Biederman <ebiederm@xmission.com> >> Cc: David S. Miller <davem@davemloft.net> >> Signed-off-by: Cong Wang <amwang@redhat.com> > > Applied but: > >> + if (np->dev_name) { >> + struct net *net = current->nsproxy->net_ns; >> + ndev = __dev_get_by_name(net, np->dev_name); >> + } > > I wonder if you should be using task_nsproxy() here. At a practical level using nsproxy straight is what we want here, as nsproxy can not be changed by anything other than the current process. So we have an implicit lock just by being the current process. Now there might be some set of rules for error checking that I am not up to speed on that says because some paths that do the rcu dance: rcu_read_lock(); nsproxy = rcu_dereference(tsk->nsproxy); net = get_net(nsproxy->net_ns); rcu_read_lock(); That all paths have to do a companion rcu dance to say this is a place where we don't need rcu protection because this is the current process and we don't need an rcu_lock here. If there is such a set of rules we have at least 24 other places in the kernel that need to be fixed. Eric -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Patch
diff --git a/net/core/netpoll.c b/net/core/netpoll.c index a6f39b6..331ccb9 100644 --- a/net/core/netpoll.c +++ b/net/core/netpoll.c @@ -1049,8 +1049,10 @@ int netpoll_setup(struct netpoll *np) int err; rtnl_lock(); - if (np->dev_name) - ndev = __dev_get_by_name(&init_net, np->dev_name); + if (np->dev_name) { + struct net *net = current->nsproxy->net_ns; + ndev = __dev_get_by_name(net, np->dev_name); + } if (!ndev) { np_err(np, "%s doesn't exist, aborting\n", np->dev_name); err = -ENODEV;