[PATCH nf] netfilter: xtables: add scheduling opportunity in get_counters

[Florian Westphal]

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 <f...@strlen.de>
---
 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 9e9d9afd18f7..14b20cf4cfd3 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 622ed2887cd5..92ef5a2ef0c3 100644
--- a/net/ipv4/netfilter/ip_tables.c
+++ b/net/ipv4/netfilter/ip_tables.c
@@ -782,6 +782,7 @@ 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 1f90644056ac..1e9c775dc3d6 100644
--- a/net/ipv6/netfilter/ip6_tables.c
+++ b/net/ipv6/netfilter/ip6_tables.c
@@ -801,6 +801,7 @@ get_counters(const struct xt_table_info *t,
 
                        ADD_COUNTER(counters[i], bcnt, pcnt);
                        ++i;
+                       cond_resched();
                }
        }
 }
-- 
2.13.0

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