[PATCH 4/9] netfilter: xtables: add scheduling opportunity in get_counters

[Pablo Neira Ayuso <pablo@netfilter.org>]

From: Florian Westphal <fw@strlen.de>

There are reports about spurious softlockups during iptables-restore, a
backtrace i saw points at get_counters -- it uses a sequence lock and also
has unbounded restart loop.

Signed-off-by: Florian Westphal <fw@strlen.de>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
 net/ipv4/netfilter/arp_tables.c | 1 +
 net/ipv4/netfilter/ip_tables.c  | 1 +
 net/ipv6/netfilter/ip6_tables.c | 1 +
 3 files changed, 3 insertions(+)

diff --git a/net/ipv4/netfilter/arp_tables.c b/net/ipv4/netfilter/arp_tables.c
index e04457198f93..9e2770fd00be 100644
--- a/net/ipv4/netfilter/arp_tables.c
+++ b/net/ipv4/netfilter/arp_tables.c
@@ -629,6 +629,7 @@ static void get_counters(const struct xt_table_info *t,
 
 			ADD_COUNTER(counters[i], bcnt, pcnt);
 			++i;
+			cond_resched();
 		}
 	}
 }
diff --git a/net/ipv4/netfilter/ip_tables.c b/net/ipv4/netfilter/ip_tables.c
index 576cba2b57e9..39286e543ee6 100644
--- a/net/ipv4/netfilter/ip_tables.c
+++ b/net/ipv4/netfilter/ip_tables.c
@@ -776,6 +776,7 @@ get_counters(const struct xt_table_info *t,
 
 			ADD_COUNTER(counters[i], bcnt, pcnt);
 			++i; /* macro does multi eval of i */
+			cond_resched();
 		}
 	}
 }
diff --git a/net/ipv6/netfilter/ip6_tables.c b/net/ipv6/netfilter/ip6_tables.c
index 54b1e75eded1..01bd3ee5ebc6 100644
--- a/net/ipv6/netfilter/ip6_tables.c
+++ b/net/ipv6/netfilter/ip6_tables.c
@@ -795,6 +795,7 @@ get_counters(const struct xt_table_info *t,
 
 			ADD_COUNTER(counters[i], bcnt, pcnt);
 			++i;
+			cond_resched();
 		}
 	}
 }
-- 
2.1.4