From: Eric Dumazet eric.duma...@gmail.com
Alex reported the following crash when using fq_codel
with htb:
crash bt
PID: 630839 TASK: 8823c990d280 CPU: 14 COMMAND: tc
[... snip ...]
#8 [8820ceec17a0] page_fault at 8160a8c2
[exception RIP: htb_qlen_notify+24]
RIP: a0841718 RSP: 8820ceec1858 RFLAGS: 00010282
RAX: RBX: RCX: 88241747b400
RDX: 88241747b408 RSI: RDI: 8811fb27d000
RBP: 8820ceec1868 R8: 88120cdeff24 R9: 88120cdeff30
R10: 0bd4 R11: a0840919 R12: a0843340
R13: R14: 0001 R15: 8808dae5c2e8
ORIG_RAX: CS: 0010 SS: 0018
#9 [...] qdisc_tree_decrease_qlen at 81565375
#10 [...] fq_codel_dequeue at a084e0a0 [sch_fq_codel]
#11 [...] fq_codel_reset at a084e2f8 [sch_fq_codel]
#12 [...] qdisc_destroy at 81560d2d
#13 [...] htb_destroy_class at a08408f8 [sch_htb]
#14 [...] htb_put at a084095c [sch_htb]
#15 [...] tc_ctl_tclass at 815645a3
#16 [...] rtnetlink_rcv_msg at 81552cb0
[... snip ...]
As Jamal pointed out, there is actually no need to call dequeue
to purge the queued skb's in reset, data structures can be just
reset explicitly. Therefore, we reset everything except config's
and stats, so that we would have a fresh start after device flipping.
Fixes: 4b549a2ef4be (fq_codel: Fair Queue Codel AQM)
Reported-by: Alex Gartrell agartr...@fb.com
Cc: Alex Gartrell agartr...@fb.com
Cc: Jamal Hadi Salim j...@mojatatu.com
Signed-off-by: Eric Dumazet eric.duma...@gmail.com
[xiyou.wangc...@gmail.com: added codel_vars_init() and
qdisc_qstats_backlog_dec()]
Signed-off-by: Cong Wang xiyou.wangc...@gmail.com
---
net/sched/sch_fq_codel.c | 22 +++---
1 file changed, 19 insertions(+), 3 deletions(-)
diff --git a/net/sched/sch_fq_codel.c b/net/sched/sch_fq_codel.c
index 21ca33c..a9ba030 100644
--- a/net/sched/sch_fq_codel.c
+++ b/net/sched/sch_fq_codel.c
@@ -288,10 +288,26 @@ static struct sk_buff *fq_codel_dequeue(struct Qdisc *sch)
static void fq_codel_reset(struct Qdisc *sch)
{
- struct sk_buff *skb;
+ struct fq_codel_sched_data *q = qdisc_priv(sch);
+ int i;
- while ((skb = fq_codel_dequeue(sch)) != NULL)
- kfree_skb(skb);
+ INIT_LIST_HEAD(q-new_flows);
+ INIT_LIST_HEAD(q-old_flows);
+ for (i = 0; i q-flows_cnt; i++) {
+ struct fq_codel_flow *flow = q-flows + i;
+
+ while (flow-head) {
+ struct sk_buff *skb = dequeue_head(flow);
+
+ qdisc_qstats_backlog_dec(sch, skb);
+ kfree_skb(skb);
+ }
+
+ INIT_LIST_HEAD(flow-flowchain);
+ codel_vars_init(flow-cvars);
+ }
+ memset(q-backlogs, 0, q-flows_cnt * sizeof(u32));
+ sch-q.qlen = 0;
}
static const struct nla_policy fq_codel_policy[TCA_FQ_CODEL_MAX + 1] = {
--
1.8.3.1
--
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