canqun zhang reported a panic BUG,kernel may panic when
unloading nf_conntrack module.
It's because we reset nf_ct_destroy to NULL when we deal
with init_net,it's too early.Some packets belongs to other
netns still refers to the conntrack.when these packets need
to be freed, kfree_skb will call nf_ct_destroy which is
NULL.
fix this bug by moving the nf_conntrack initialize and cleanup
codes out of the pernet operations,this job should be done
in module_init/exit.We can't use init_net to identify if
it's the right time.
Reported-by: canqun zhang <canqunzhang@xxxxxxxxx>
Signed-off-by: Gao feng <gaofeng@xxxxxxxxxxxxxx>
---
include/net/netfilter/nf_conntrack_core.h | 10 +++-
net/netfilter/nf_conntrack_core.c | 99 ++++++++++++-------------------
net/netfilter/nf_conntrack_standalone.c | 29 ++++++---
3 files changed, 67 insertions(+), 71 deletions(-)
diff --git a/include/net/netfilter/nf_conntrack_core.h b/include/net/netfilter/nf_conntrack_core.h
index d8f5b9f..ec51a3c 100644
--- a/include/net/netfilter/nf_conntrack_core.h
+++ b/include/net/netfilter/nf_conntrack_core.h
@@ -25,8 +25,14 @@ extern unsigned int nf_conntrack_in(struct net *net,
unsigned int hooknum,
struct sk_buff *skb);
-extern int nf_conntrack_init(struct net *net);
-extern void nf_conntrack_cleanup(struct net *net);
+extern int nf_conntrack_init_net(struct net *net);
+extern void nf_conntrack_cleanup_net(struct net *net);
+
+extern int nf_conntrack_init_start(void);
+extern void nf_conntrack_cleanup_start(void);
+
+extern void nf_conntrack_init_end(void);
+extern void nf_conntrack_cleanup_end(void);
extern int nf_conntrack_proto_init(struct net *net);
extern void nf_conntrack_proto_fini(struct net *net);
diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c
index 08cdc71..ffb2463 100644
--- a/net/netfilter/nf_conntrack_core.c
+++ b/net/netfilter/nf_conntrack_core.c
@@ -1331,18 +1331,23 @@ static int untrack_refs(void)
return cnt;
}
-static void nf_conntrack_cleanup_init_net(void)
+void nf_conntrack_cleanup_start(void)
{
- while (untrack_refs() > 0)
- schedule();
-
-#ifdef CONFIG_NF_CONNTRACK_ZONES
- nf_ct_extend_unregister(&nf_ct_zone_extend);
-#endif
+ RCU_INIT_POINTER(ip_ct_attach, NULL);
}
-static void nf_conntrack_cleanup_net(struct net *net)
+/*
+ * Mishearing the voices in his head, our hero wonders how he's
+ * supposed to kill the mall.
+ */
+void nf_conntrack_cleanup_net(struct net *net)
{
+ /*
+ * This makes sure all current packets have passed through
+ * netfilter framework. Roll on, two-stage module
+ * delete...
+ */
+ synchronize_net();
i_see_dead_people:
nf_ct_iterate_cleanup(net, kill_all, NULL);
nf_ct_release_dying_list(net);
@@ -1352,6 +1357,7 @@ static void nf_conntrack_cleanup_net(struct net *net)
}
nf_ct_free_hashtable(net->ct.hash, net->ct.htable_size);
+ nf_conntrack_proto_fini(net);
nf_conntrack_helper_fini(net);
nf_conntrack_timeout_fini(net);
nf_conntrack_ecache_fini(net);
@@ -1363,24 +1369,15 @@ static void nf_conntrack_cleanup_net(struct net *net)
free_percpu(net->ct.stat);
}
-/* Mishearing the voices in his head, our hero wonders how he's
- supposed to kill the mall. */
-void nf_conntrack_cleanup(struct net *net)
+void nf_conntrack_cleanup_end(void)
{
- if (net_eq(net, &init_net))
- RCU_INIT_POINTER(ip_ct_attach, NULL);
-
- /* This makes sure all current packets have passed through
- netfilter framework. Roll on, two-stage module
- delete... */
- synchronize_net();
- nf_conntrack_proto_fini(net);
- nf_conntrack_cleanup_net(net);
+ RCU_INIT_POINTER(nf_ct_destroy, NULL);
+ while (untrack_refs() > 0)
+ schedule();
- if (net_eq(net, &init_net)) {
- RCU_INIT_POINTER(nf_ct_destroy, NULL);
- nf_conntrack_cleanup_init_net();
- }
+#ifdef CONFIG_NF_CONNTRACK_ZONES
+ nf_ct_extend_unregister(&nf_ct_zone_extend);
+#endif
}
void *nf_ct_alloc_hashtable(unsigned int *sizep, int nulls)
@@ -1473,7 +1470,7 @@ void nf_ct_untracked_status_or(unsigned long bits)
}
EXPORT_SYMBOL_GPL(nf_ct_untracked_status_or);
-static int nf_conntrack_init_init_net(void)
+int nf_conntrack_init_start(void)
{
int max_factor = 8;
int ret, cpu;
@@ -1527,7 +1524,7 @@ err_extend:
#define UNCONFIRMED_NULLS_VAL ((1<<30)+0)
#define DYING_NULLS_VAL ((1<<30)+1)
-static int nf_conntrack_init_net(struct net *net)
+int nf_conntrack_init_net(struct net *net)
{
int ret;
@@ -1580,7 +1577,12 @@ static int nf_conntrack_init_net(struct net *net)
ret = nf_conntrack_helper_init(net);
if (ret < 0)
goto err_helper;
+ ret = nf_conntrack_proto_init(net);
+ if (ret < 0)
+ goto out_proto;
return 0;
+out_proto:
+ nf_conntrack_helper_fini(net);
err_helper:
nf_conntrack_timeout_fini(net);
err_timeout:
@@ -1603,42 +1605,17 @@ err_stat:
return ret;
}
+void nf_conntrack_init_end(void)
+{
+ /* For use by REJECT target */
+ RCU_INIT_POINTER(ip_ct_attach, nf_conntrack_attach);
+ RCU_INIT_POINTER(nf_ct_destroy, destroy_conntrack);
+
+ /* Howto get NAT offsets */
+ RCU_INIT_POINTER(nf_ct_nat_offset, NULL);
+}
+
s16 (*nf_ct_nat_offset)(const struct nf_conn *ct,
enum ip_conntrack_dir dir,
u32 seq);
EXPORT_SYMBOL_GPL(nf_ct_nat_offset);
-
-int nf_conntrack_init(struct net *net)
-{
- int ret;
-
- if (net_eq(net, &init_net)) {
- ret = nf_conntrack_init_init_net();
- if (ret < 0)
- goto out_init_net;
- }
- ret = nf_conntrack_proto_init(net);
- if (ret < 0)
- goto out_proto;
- ret = nf_conntrack_init_net(net);
- if (ret < 0)
- goto out_net;
-
- if (net_eq(net, &init_net)) {
- /* For use by REJECT target */
- RCU_INIT_POINTER(ip_ct_attach, nf_conntrack_attach);
- RCU_INIT_POINTER(nf_ct_destroy, destroy_conntrack);
-
- /* Howto get NAT offsets */
- RCU_INIT_POINTER(nf_ct_nat_offset, NULL);
- }
- return 0;
-
-out_net:
- nf_conntrack_proto_fini(net);
-out_proto:
- if (net_eq(net, &init_net))
- nf_conntrack_cleanup_init_net();
-out_init_net:
- return ret;
-}
diff --git a/net/netfilter/nf_conntrack_standalone.c b/net/netfilter/nf_conntrack_standalone.c
index 363285d..00bf93c 100644
--- a/net/netfilter/nf_conntrack_standalone.c
+++ b/net/netfilter/nf_conntrack_standalone.c
@@ -530,11 +530,11 @@ static void nf_conntrack_standalone_fini_sysctl(struct net *net)
}
#endif /* CONFIG_SYSCTL */
-static int nf_conntrack_net_init(struct net *net)
+static int nf_conntrack_pernet_init(struct net *net)
{
int ret;
- ret = nf_conntrack_init(net);
+ ret = nf_conntrack_init_net(net);
if (ret < 0)
goto out_init;
ret = nf_conntrack_standalone_init_proc(net);
@@ -550,31 +550,44 @@ static int nf_conntrack_net_init(struct net *net)
out_sysctl:
nf_conntrack_standalone_fini_proc(net);
out_proc:
- nf_conntrack_cleanup(net);
+ nf_conntrack_cleanup_net(net);
out_init:
return ret;
}
-static void nf_conntrack_net_exit(struct net *net)
+static void nf_conntrack_pernet_exit(struct net *net)
{
nf_conntrack_standalone_fini_sysctl(net);
nf_conntrack_standalone_fini_proc(net);
- nf_conntrack_cleanup(net);
+ nf_conntrack_cleanup_net(net);
}
static struct pernet_operations nf_conntrack_net_ops = {
- .init = nf_conntrack_net_init,
- .exit = nf_conntrack_net_exit,
+ .init = nf_conntrack_pernet_init,
+ .exit = nf_conntrack_pernet_exit,
};
static int __init nf_conntrack_standalone_init(void)
{
- return register_pernet_subsys(&nf_conntrack_net_ops);
+ int ret = nf_conntrack_init_start();
+ if (ret < 0)
+ goto out_start;
+ ret = register_pernet_subsys(&nf_conntrack_net_ops);
+ if (ret < 0)
+ goto out_pernet;
+ nf_conntrack_init_end();
+ return 0;
+out_pernet:
+ nf_conntrack_cleanup_end();
+out_start:
+ return ret;
}
static void __exit nf_conntrack_standalone_fini(void)
{
+ nf_conntrack_cleanup_start();
unregister_pernet_subsys(&nf_conntrack_net_ops);
+ nf_conntrack_cleanup_end();
}
module_init(nf_conntrack_standalone_init);
--
1.7.11.7
--
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