Re: [PATCH net-next] pkt_sched: fq: use proper locking in fq_dump_stats()

[David Miller]

From: Eric Dumazet 
Date: Thu, 15 Sep 2016 16:20:01 -0700

> From: Eric Dumazet 
> 
> When fq is used on 32bit kernels, we need to lock the qdisc before
> copying 64bit fields.
> 
> Otherwise "tc -s qdisc ..." might report bogus values.
> 
> Fixes: afe4fd062416 ("pkt_sched: fq: Fair Queue packet scheduler")
> Signed-off-by: Eric Dumazet 

Applied.

[PATCH net-next] pkt_sched: fq: use proper locking in fq_dump_stats()

[Eric Dumazet]

From: Eric Dumazet 

When fq is used on 32bit kernels, we need to lock the qdisc before
copying 64bit fields.

Otherwise "tc -s qdisc ..." might report bogus values.

Fixes: afe4fd062416 ("pkt_sched: fq: Fair Queue packet scheduler")
Signed-off-by: Eric Dumazet 
---
 net/sched/sch_fq.c |   32 ++--
 1 file changed, 18 insertions(+), 14 deletions(-)

diff --git a/net/sched/sch_fq.c b/net/sched/sch_fq.c
index e5458b99e09c..dc52cc10d6ed 100644
--- a/net/sched/sch_fq.c
+++ b/net/sched/sch_fq.c
@@ -823,20 +823,24 @@ nla_put_failure:
 static int fq_dump_stats(struct Qdisc *sch, struct gnet_dump *d)
 {
struct fq_sched_data *q = qdisc_priv(sch);
-   u64 now = ktime_get_ns();
-   struct tc_fq_qd_stats st = {
-   .gc_flows   = q->stat_gc_flows,
-   .highprio_packets   = q->stat_internal_packets,
-   .tcp_retrans= q->stat_tcp_retrans,
-   .throttled  = q->stat_throttled,
-   .flows_plimit   = q->stat_flows_plimit,
-   .pkts_too_long  = q->stat_pkts_too_long,
-   .allocation_errors  = q->stat_allocation_errors,
-   .flows  = q->flows,
-   .inactive_flows = q->inactive_flows,
-   .throttled_flows= q->throttled_flows,
-   .time_next_delayed_flow = q->time_next_delayed_flow - now,
-   };
+   struct tc_fq_qd_stats st;
+
+   sch_tree_lock(sch);
+
+   st.gc_flows   = q->stat_gc_flows;
+   st.highprio_packets   = q->stat_internal_packets;
+   st.tcp_retrans= q->stat_tcp_retrans;
+   st.throttled  = q->stat_throttled;
+   st.flows_plimit   = q->stat_flows_plimit;
+   st.pkts_too_long  = q->stat_pkts_too_long;
+   st.allocation_errors  = q->stat_allocation_errors;
+   st.time_next_delayed_flow = q->time_next_delayed_flow - ktime_get_ns();
+   st.flows  = q->flows;
+   st.inactive_flows = q->inactive_flows;
+   st.throttled_flows= q->throttled_flows;
+   st.pad= 0;
+
+   sch_tree_unlock(sch);
 
return gnet_stats_copy_app(d, , sizeof(st));
 }