| Message ID | 1306344844.11400.11.camel@edumazet-laptop |
|---|---|
| State | Accepted, archived |
| Delegated to: | David Miller |
| Headers | show |
From: Eric Dumazet <eric.dumazet@gmail.com> Date: Wed, 25 May 2011 19:34:04 +0200 > Commit e67f88dd12f6 (dont hold rtnl mutex during netlink dump callbacks) > missed fact that rtnl_fill_ifinfo() must be called with rtnl held. > > Because of possible deadlocks between two mutexes (cb_mutex and rtnl), > its not easy to solve this problem, so revert this part of the patch. > > It also forgot one rcu_read_unlock() in FIB dump_rules() > > Add one ASSERT_RTNL() in rtnl_fill_ifinfo() to remind us the rule. > > Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> > CC: Patrick McHardy <kaber@trash.net> > CC: Stephen Hemminger <shemminger@vyatta.com> > --- > I tried to solve this problem differently but failed. We need more > preliminary steps. Applied. -- 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
diff --git a/net/core/fib_rules.c b/net/core/fib_rules.c index 3911586..008dc70 100644 --- a/net/core/fib_rules.c +++ b/net/core/fib_rules.c @@ -602,6 +602,7 @@ static int dump_rules(struct sk_buff *skb, struct netlink_callback *cb, skip: idx++; } + rcu_read_unlock(); cb->args[1] = idx; rules_ops_put(ops); diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c index d1644e3..2d56cb9 100644 --- a/net/core/rtnetlink.c +++ b/net/core/rtnetlink.c @@ -850,6 +850,7 @@ static int rtnl_fill_ifinfo(struct sk_buff *skb, struct net_device *dev, struct nlattr *attr, *af_spec; struct rtnl_af_ops *af_ops; + ASSERT_RTNL(); nlh = nlmsg_put(skb, pid, seq, type, sizeof(*ifm), flags); if (nlh == NULL) return -EMSGSIZE; @@ -1876,6 +1877,7 @@ static int rtnetlink_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh) int min_len; int family; int type; + int err; type = nlh->nlmsg_type; if (type > RTM_MAX) @@ -1902,8 +1904,11 @@ static int rtnetlink_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh) if (dumpit == NULL) return -EOPNOTSUPP; + __rtnl_unlock(); rtnl = net->rtnl; - return netlink_dump_start(rtnl, skb, nlh, dumpit, NULL); + err = netlink_dump_start(rtnl, skb, nlh, dumpit, NULL); + rtnl_lock(); + return err; } memset(rta_buf, 0, (rtattr_max * sizeof(struct rtattr *))); @@ -1975,7 +1980,7 @@ static int __net_init rtnetlink_net_init(struct net *net) { struct sock *sk; sk = netlink_kernel_create(net, NETLINK_ROUTE, RTNLGRP_MAX, - rtnetlink_rcv, NULL, THIS_MODULE); + rtnetlink_rcv, &rtnl_mutex, THIS_MODULE); if (!sk) return -ENOMEM; net->rtnl = sk;
Commit e67f88dd12f6 (dont hold rtnl mutex during netlink dump callbacks) missed fact that rtnl_fill_ifinfo() must be called with rtnl held. Because of possible deadlocks between two mutexes (cb_mutex and rtnl), its not easy to solve this problem, so revert this part of the patch. It also forgot one rcu_read_unlock() in FIB dump_rules() Add one ASSERT_RTNL() in rtnl_fill_ifinfo() to remind us the rule. Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> CC: Patrick McHardy <kaber@trash.net> CC: Stephen Hemminger <shemminger@vyatta.com> --- I tried to solve this problem differently but failed. We need more preliminary steps. net/core/fib_rules.c | 1 + net/core/rtnetlink.c | 9 +++++++-- 2 files changed, 8 insertions(+), 2 deletions(-) -- 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