net: ipv4: fix schedule while atomic bug in check_lifetime()

move might_sleep operations out of the rcu_read_lock() section.
Also fix iterating over ifa_dev->ifa_list

Introduced by: commit 5c766d642bcaf "ipv4: introduce address lifetime"

Signed-off-by: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
index 00386e02e708e540bf1adca821806a89255302ea..c6287cd978c2db7b40f3aa3fe06b5d43bced64d5 100644 (file)
--- a/net/ipv4/devinet.c
+++ b/net/ipv4/devinet.c
@@ -587,13 +587,16 @@ static void check_lifetime(struct work_struct *work)
 {
        unsigned long now, next, next_sec, next_sched;
        struct in_ifaddr *ifa;
+       struct hlist_node *n;
        int i;
 
        now = jiffies;
        next = round_jiffies_up(now + ADDR_CHECK_FREQUENCY);
 
-       rcu_read_lock();
        for (i = 0; i < IN4_ADDR_HSIZE; i++) {
+               bool change_needed = false;
+
+               rcu_read_lock();
                hlist_for_each_entry_rcu(ifa, &inet_addr_lst[i], hash) {
                        unsigned long age;
 
@@ -606,16 +609,7 @@ static void check_lifetime(struct work_struct *work)
 
                        if (ifa->ifa_valid_lft != INFINITY_LIFE_TIME &&
                            age >= ifa->ifa_valid_lft) {
-                               struct in_ifaddr **ifap ;
-
-                               rtnl_lock();
-                               for (ifap = &ifa->ifa_dev->ifa_list;
-                                    *ifap != NULL; ifap = &ifa->ifa_next) {
-                                       if (*ifap == ifa)
-                                               inet_del_ifa(ifa->ifa_dev,
-                                                            ifap, 1);
-                               }
-                               rtnl_unlock();
+                               change_needed = true;
                        } else if (ifa->ifa_preferred_lft ==
                                   INFINITY_LIFE_TIME) {
                                continue;
@@ -625,10 +619,8 @@ static void check_lifetime(struct work_struct *work)
                                        next = ifa->ifa_tstamp +
                                               ifa->ifa_valid_lft * HZ;
 
-                               if (!(ifa->ifa_flags & IFA_F_DEPRECATED)) {
-                                       ifa->ifa_flags |= IFA_F_DEPRECATED;
-                                       rtmsg_ifa(RTM_NEWADDR, ifa, NULL, 0);
-                               }
+                               if (!(ifa->ifa_flags & IFA_F_DEPRECATED))
+                                       change_needed = true;
                        } else if (time_before(ifa->ifa_tstamp +
                                               ifa->ifa_preferred_lft * HZ,
                                               next)) {
@@ -636,8 +628,42 @@ static void check_lifetime(struct work_struct *work)
                                       ifa->ifa_preferred_lft * HZ;
                        }
                }
+               rcu_read_unlock();
+               if (!change_needed)
+                       continue;
+               rtnl_lock();
+               hlist_for_each_entry_safe(ifa, n, &inet_addr_lst[i], hash) {
+                       unsigned long age;
+
+                       if (ifa->ifa_flags & IFA_F_PERMANENT)
+                               continue;
+
+                       /* We try to batch several events at once. */
+                       age = (now - ifa->ifa_tstamp +
+                              ADDRCONF_TIMER_FUZZ_MINUS) / HZ;
+
+                       if (ifa->ifa_valid_lft != INFINITY_LIFE_TIME &&
+                           age >= ifa->ifa_valid_lft) {
+                               struct in_ifaddr **ifap;
+
+                               for (ifap = &ifa->ifa_dev->ifa_list;
+                                    *ifap != NULL; ifap = &(*ifap)->ifa_next) {
+                                       if (*ifap == ifa) {
+                                               inet_del_ifa(ifa->ifa_dev,
+                                                            ifap, 1);
+                                               break;
+                                       }
+                               }
+                       } else if (ifa->ifa_preferred_lft !=
+                                  INFINITY_LIFE_TIME &&
+                                  age >= ifa->ifa_preferred_lft &&
+                                  !(ifa->ifa_flags & IFA_F_DEPRECATED)) {
+                               ifa->ifa_flags |= IFA_F_DEPRECATED;
+                               rtmsg_ifa(RTM_NEWADDR, ifa, NULL, 0);
+                       }
+               }
+               rtnl_unlock();
        }
-       rcu_read_unlock();
 
        next_sec = round_jiffies_up(next);
        next_sched = next;