From: Nikolay Aleksandrov <niko...@cumulusnetworks.com>
br_fill_ifinfo is called by br_ifinfo_notify which can be called from
many contexts with different locks held, sometimes it relies upon
bridge's spinlock only which is a problem for the vlan code, so use
explicitly rcu for that to avoid problems.
Signed-off-by: Nikolay Aleksandrov <niko...@cumulusnetworks.com>
---
net/bridge/br_netlink.c | 21 +++++++++++++--------
1 file changed, 13 insertions(+), 8 deletions(-)
diff --git a/net/bridge/br_netlink.c b/net/bridge/br_netlink.c
index edee48e9aa8f..e27bde2642cc 100644
--- a/net/bridge/br_netlink.c
+++ b/net/bridge/br_netlink.c
@@ -253,7 +253,7 @@ static int br_fill_ifvlaninfo_compressed(struct sk_buff
*skb,
* if vlaninfo represents a range
*/
pvid = br_get_pvid(vg);
- list_for_each_entry(v, &vg->vlan_list, vlist) {
+ list_for_each_entry_rcu(v, &vg->vlan_list, vlist) {
flags = 0;
if (!br_vlan_should_use(v))
continue;
@@ -303,7 +303,7 @@ static int br_fill_ifvlaninfo(struct sk_buff *skb,
u16 pvid;
pvid = br_get_pvid(vg);
- list_for_each_entry(v, &vg->vlan_list, vlist) {
+ list_for_each_entry_rcu(v, &vg->vlan_list, vlist) {
if (!br_vlan_should_use(v))
continue;
@@ -386,22 +386,27 @@ static int br_fill_ifinfo(struct sk_buff *skb,
struct nlattr *af;
int err;
+ /* RCU needed because of the VLAN locking rules (rcu || rtnl) */
+ rcu_read_lock();
if (port)
- vg = nbp_vlan_group(port);
+ vg = nbp_vlan_group_rcu(port);
else
- vg = br_vlan_group(br);
+ vg = br_vlan_group_rcu(br);
- if (!vg || !vg->num_vlans)
+ if (!vg || !vg->num_vlans) {
+ rcu_read_unlock();
goto done;
-
+ }
af = nla_nest_start(skb, IFLA_AF_SPEC);
- if (!af)
+ if (!af) {
+ rcu_read_unlock();
goto nla_put_failure;
-
+ }
if (filter_mask & RTEXT_FILTER_BRVLAN_COMPRESSED)
err = br_fill_ifvlaninfo_compressed(skb, vg);
else
err = br_fill_ifvlaninfo(skb, vg);
+ rcu_read_unlock();
if (err)
goto nla_put_failure;
nla_nest_end(skb, af);
--
2.4.3
--
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