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Diffstat (limited to 'net/mctp/device.c')
-rw-r--r--net/mctp/device.c34
1 files changed, 25 insertions, 9 deletions
diff --git a/net/mctp/device.c b/net/mctp/device.c
index ef2755f82f87..f49be882e98e 100644
--- a/net/mctp/device.c
+++ b/net/mctp/device.c
@@ -6,6 +6,7 @@
* Copyright (c) 2021 Google
*/
+#include <linux/if_arp.h>
#include <linux/if_link.h>
#include <linux/mctp.h>
#include <linux/netdevice.h>
@@ -24,12 +25,25 @@ struct mctp_dump_cb {
size_t a_idx;
};
-/* unlocked: caller must hold rcu_read_lock */
+/* unlocked: caller must hold rcu_read_lock.
+ * Returned mctp_dev has its refcount incremented, or NULL if unset.
+ */
struct mctp_dev *__mctp_dev_get(const struct net_device *dev)
{
- return rcu_dereference(dev->mctp_ptr);
+ struct mctp_dev *mdev = rcu_dereference(dev->mctp_ptr);
+
+ /* RCU guarantees that any mdev is still live.
+ * Zero refcount implies a pending free, return NULL.
+ */
+ if (mdev)
+ if (!refcount_inc_not_zero(&mdev->refs))
+ return NULL;
+ return mdev;
}
+/* Returned mctp_dev does not have refcount incremented. The returned pointer
+ * remains live while rtnl_lock is held, as that prevents mctp_unregister()
+ */
struct mctp_dev *mctp_dev_get_rtnl(const struct net_device *dev)
{
return rtnl_dereference(dev->mctp_ptr);
@@ -106,7 +120,7 @@ static int mctp_dump_addrinfo(struct sk_buff *skb, struct netlink_callback *cb)
struct ifaddrmsg *hdr;
struct mctp_dev *mdev;
int ifindex;
- int idx, rc;
+ int idx = 0, rc;
hdr = nlmsg_data(cb->nlh);
// filter by ifindex if requested
@@ -123,6 +137,7 @@ static int mctp_dump_addrinfo(struct sk_buff *skb, struct netlink_callback *cb)
if (mdev) {
rc = mctp_dump_dev_addrinfo(mdev,
skb, cb);
+ mctp_dev_put(mdev);
// Error indicates full buffer, this
// callback will get retried.
if (rc < 0)
@@ -208,7 +223,7 @@ static int mctp_rtm_newaddr(struct sk_buff *skb, struct nlmsghdr *nlh,
if (!mdev)
return -ENODEV;
- if (!mctp_address_ok(addr->s_addr))
+ if (!mctp_address_unicast(addr->s_addr))
return -EINVAL;
/* Prevent duplicates. Under RTNL so don't need to lock for reading */
@@ -297,7 +312,7 @@ void mctp_dev_hold(struct mctp_dev *mdev)
void mctp_dev_put(struct mctp_dev *mdev)
{
- if (refcount_dec_and_test(&mdev->refs)) {
+ if (mdev && refcount_dec_and_test(&mdev->refs)) {
dev_put(mdev->dev);
kfree_rcu(mdev, rcu);
}
@@ -369,6 +384,7 @@ static size_t mctp_get_link_af_size(const struct net_device *dev,
if (!mdev)
return 0;
ret = nla_total_size(4); /* IFLA_MCTP_NET */
+ mctp_dev_put(mdev);
return ret;
}
@@ -412,10 +428,10 @@ static void mctp_unregister(struct net_device *dev)
struct mctp_dev *mdev;
mdev = mctp_dev_get_rtnl(dev);
- if (mctp_known(dev) != (bool)mdev) {
+ if (mdev && !mctp_known(dev)) {
// Sanity check, should match what was set in mctp_register
- netdev_warn(dev, "%s: mdev pointer %d but type (%d) match is %d",
- __func__, (bool)mdev, mctp_known(dev), dev->type);
+ netdev_warn(dev, "%s: BUG mctp_ptr set for unknown type %d",
+ __func__, dev->type);
return;
}
if (!mdev)
@@ -439,7 +455,7 @@ static int mctp_register(struct net_device *dev)
if (mdev) {
if (!mctp_known(dev))
- netdev_warn(dev, "%s: mctp_dev set for unknown type %d",
+ netdev_warn(dev, "%s: BUG mctp_ptr set for unknown type %d",
__func__, dev->type);
return 0;
}