[PATCH 3.14 105/140] net: sched: lock imbalance in hhf qdisc

Greg Kroah-Hartman
2014-05-29T04:35:46Z

From: John Fastabend <john.fastabend@gmail.com>

[ Upstream commit f6a082fed1e6407c2f4437d0d963b1bcbe5f9f58 ]

hhf_change() takes the sch_tree_lock and releases it but misses the
error cases. Fix the missed case here.

To reproduce try a command like this,

# tc qdisc change dev p3p2 root hhf quantum 40960 non_hh_weight 300000

Signed-off-by: John Fastabend <john.r.fastabend@intel.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/sched/sch_hhf.c | 11 ++++++-----
1 file changed, 6 insertions(+), 5 deletions(-)

--- a/net/sched/sch_hhf.c
+++ b/net/sched/sch_hhf.c
@@ -553,11 +553,6 @@ static int hhf_change(struct Qdisc *sch,
if (err < 0)
return err;

- sch_tree_lock(sch);
-
- if (tb[TCA_HHF_BACKLOG_LIMIT])
- sch->limit = nla_get_u32(tb[TCA_HHF_BACKLOG_LIMIT]);
-
if (tb[TCA_HHF_QUANTUM])
new_quantum = nla_get_u32(tb[TCA_HHF_QUANTUM]);

@@ -567,6 +562,12 @@ static int hhf_change(struct Qdisc *sch,
non_hh_quantum = (u64)new_quantum * new_hhf_non_hh_weight;
if (non_hh_quantum > INT_MAX)
return -EINVAL;
+
+ sch_tree_lock(sch);
+
+ if (tb[TCA_HHF_BACKLOG_LIMIT])
+ sch->limit = nla_get_u32(tb[TCA_HHF_BACKLOG_LIMIT]);
+
q->quantum = new_quantum;
q->hhf_non_hh_weight = new_hhf_non_hh_weight;