3.16.60-rc1 review patch. If anyone has any objections, please let me know.
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From: Eric Dumazet edumazet@google.com
commit 7df40c2673a1307c3260aab6f9d4b9bf97ca8fd7 upstream.
Normally, a socket can not be freed/reused unless all its TX packets left qdisc and were TX-completed. However connect(AF_UNSPEC) allows this to happen.
With commit fc59d5bdf1e3 ("pkt_sched: fq: clear time_next_packet for reused flows") we cleared f->time_next_packet but took no special action if the flow was still in the throttled rb-tree.
Since f->time_next_packet is the key used in the rb-tree searches, blindly clearing it might break rb-tree integrity. We need to make sure the flow is no longer in the rb-tree to avoid this problem.
Fixes: fc59d5bdf1e3 ("pkt_sched: fq: clear time_next_packet for reused flows") Signed-off-by: Eric Dumazet edumazet@google.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Ben Hutchings ben@decadent.org.uk --- net/sched/sch_fq.c | 37 +++++++++++++++++++++++++------------ 1 file changed, 25 insertions(+), 12 deletions(-)
--- a/net/sched/sch_fq.c +++ b/net/sched/sch_fq.c @@ -124,6 +124,28 @@ static bool fq_flow_is_detached(const st return f->next == &detached; }
+static bool fq_flow_is_throttled(const struct fq_flow *f) +{ + return f->next == &throttled; +} + +static void fq_flow_add_tail(struct fq_flow_head *head, struct fq_flow *flow) +{ + if (head->first) + head->last->next = flow; + else + head->first = flow; + head->last = flow; + flow->next = NULL; +} + +static void fq_flow_unset_throttled(struct fq_sched_data *q, struct fq_flow *f) +{ + rb_erase(&f->rate_node, &q->delayed); + q->throttled_flows--; + fq_flow_add_tail(&q->old_flows, f); +} + static void fq_flow_set_throttled(struct fq_sched_data *q, struct fq_flow *f) { struct rb_node **p = &q->delayed.rb_node, *parent = NULL; @@ -151,15 +173,6 @@ static void fq_flow_set_throttled(struct
static struct kmem_cache *fq_flow_cachep __read_mostly;
-static void fq_flow_add_tail(struct fq_flow_head *head, struct fq_flow *flow) -{ - if (head->first) - head->last->next = flow; - else - head->first = flow; - head->last = flow; - flow->next = NULL; -}
/* limit number of collected flows per round */ #define FQ_GC_MAX 8 @@ -251,6 +264,8 @@ static struct fq_flow *fq_classify(struc f->socket_hash != sk->sk_hash)) { f->credit = q->initial_quantum; f->socket_hash = sk->sk_hash; + if (fq_flow_is_throttled(f)) + fq_flow_unset_throttled(q, f); f->time_next_packet = 0ULL; } return f; @@ -407,9 +422,7 @@ static void fq_check_throttled(struct fq q->time_next_delayed_flow = f->time_next_packet; break; } - rb_erase(p, &q->delayed); - q->throttled_flows--; - fq_flow_add_tail(&q->old_flows, f); + fq_flow_unset_throttled(q, f); } }