"tc filter show" does not show last U32 filter on 32-bit systems (tested on
x86).
Additional condition: filter does not have action and CONFIG_NET_CLS_ACT=y
Example: tc filter add dev eth0 parent 1:0 protocol ip prio 100 u32 match ip
dst 10.200.2.2 flowid 1:20
Function tcf_action_copy_stats() returns an error because the (struct tc_action
*)a->priv is NULL (for 32bit systems).
The sequence of calls:
u32_dump()
cls_u32.c:1009 if (tcf_exts_dump_stats(skb, &n->exts) < 0) goto
nla_put_failure;
tcf_exts_dump_stats()
cls_api.c:606 if (tcf_action_copy_stats(skb, a, 1) < 0) return -1;
tcf_action_copy_stats()
act_api.c:604 struct tcf_common *p = a->priv;
act_api.c:606 if (p == NULL) goto errout; // return -1;
One of variants correcting this error is a verify the existence of action
before calling tcf_action_copy_stats().
Patch for kernel 3.18.10
diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c
index aad6a67..8e7ad61 100644
--- a/net/sched/cls_api.c
+++ b/net/sched/cls_api.c
@@ -602,9 +602,11 @@ EXPORT_SYMBOL(tcf_exts_dump);
int tcf_exts_dump_stats(struct sk_buff *skb, struct tcf_exts *exts)
{
#ifdef CONFIG_NET_CLS_ACT
- struct tc_action *a = tcf_exts_first_act(exts);
- if (tcf_action_copy_stats(skb, a, 1) < 0)
- return -1;
+ if(tcf_exts_is_available(exts)) {
+ struct tc_action *a = tcf_exts_first_act(exts);
+ if (tcf_action_copy_stats(skb, a, 1) < 0)
+ return -1;
+ }
#endif
return 0;
}
This will fix the bug 84661 https://bugzilla.kernel.org/show_bug.cgi?id=84661
In 64bit system a->priv is not NULL, but is not a valid pointer, but because of
a->type == 0 and
compat_mode == 1 returns a value 0.
"tc filter show dev eth0".
------------------------
tc filter add dev eth0 parent 1:0 protocol ip prio 100 u32 match ip dst
10.200.2.2 flowid 1:20
tc filter add dev eth0 parent 1:0 protocol ip prio 100 u32 match ip dst
10.200.2.3 flowid 1:30
tc filter show dev eth0
....
(1) filter parent 1: protocol ip pref 100 u32 fh 800::800 order 2048 key ht 800
bkt 0 flowid 1:20
match 0ac80202/ffffffff at 16
(2) filter parent 1: protocol ip pref 100 u32 fh 800::801 order 2049 key ht 800
bkt 0 flowid 1:30
match 0ac80203/ffffffff at 16
------------------------
64bit system
(1) a->priv == 0x80000800
(2) a->priv == 0x80000801
32bit system
(1) a->priv == 0x0
(2) a->priv == 0x0
I could not understand the reason for this difference between 32-bit and 64-bit
systems.
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