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>

1 files changed, 42 insertions, 16 deletions

diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
index 00386e02e708..c6287cd978c2 100644
--- 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;