netfilter: {ip,ip6,arp}_tables: avoid lockdep false positive

After commit 24b36f019 (netfilter: {ip,ip6,arp}_tables: dont block
bottom half more than necessary), lockdep can raise a warning
because we attempt to lock a spinlock with BH enabled, while
the same lock is usually locked by another cpu in a softirq context.

Disable again BH to avoid these lockdep warnings.

Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Diagnosed-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 4 insertions, 0 deletions

diff --git a/net/ipv4/netfilter/arp_tables.c b/net/ipv4/netfilter/arp_tables.c
index 6bccba31d132..51d6c3167975 100644
--- a/net/ipv4/netfilter/arp_tables.c
+++ b/net/ipv4/netfilter/arp_tables.c
@@ -735,6 +735,7 @@ static void get_counters(const struct xt_table_info *t,
                 if (cpu == curcpu)
                         continue;
                 i = 0;
+                local_bh_disable();
                 xt_info_wrlock(cpu);
                 xt_entry_foreach(iter, t->entries[cpu], t->size) {
                         ADD_COUNTER(counters[i], iter->counters.bcnt,
@@ -742,6 +743,7 @@ static void get_counters(const struct xt_table_info *t,
                         ++i;
                 }
                 xt_info_wrunlock(cpu);
+                local_bh_enable();
         }
         put_cpu();
 }
diff --git a/net/ipv4/netfilter/ip_tables.c b/net/ipv4/netfilter/ip_tables.c
index c439721b165a..97b64b22c412 100644
--- a/net/ipv4/netfilter/ip_tables.c
+++ b/net/ipv4/netfilter/ip_tables.c
@@ -909,6 +909,7 @@ get_counters(const struct xt_table_info *t,
                 if (cpu == curcpu)
                         continue;
                 i = 0;
+                local_bh_disable();
                 xt_info_wrlock(cpu);
                 xt_entry_foreach(iter, t->entries[cpu], t->size) {
                         ADD_COUNTER(counters[i], iter->counters.bcnt,
@@ -916,6 +917,7 @@ get_counters(const struct xt_table_info *t,
                         ++i; /* macro does multi eval of i */
                 }
                 xt_info_wrunlock(cpu);
+                local_bh_enable();
         }
         put_cpu();
 }