When we exceed current packets limit and have more than one
segment in the list returned by skb_gso_segment(), netem drops
only the first one, skipping the rest, hence kmemleak reports:
unreferenced object 0xffff880b5d23b600 (size 1024):
comm "softirq", pid 0, jiffies 4384527763 (age 2770.629s)
hex dump (first 32 bytes):
00 80 23 5d 0b 88 ff ff 00 00 00 00 00 00 00 00 ..#]............
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
backtrace:
[<00000000d8a19b9d>] __alloc_skb+0xc9/0x520
[<000000001709b32f>] skb_segment+0x8c8/0x3710
[<00000000c7b9bb88>] tcp_gso_segment+0x331/0x1830
[<00000000c921cba1>] inet_gso_segment+0x476/0x1370
[<000000008b762dd4>] skb_mac_gso_segment+0x1f9/0x510
[<000000002182660a>] __skb_gso_segment+0x1dd/0x620
[<00000000412651b9>] netem_enqueue+0x1536/0x2590 [sch_netem]
[<0000000005d3b2a9>] __dev_queue_xmit+0x1167/0x2120
[<00000000fc5f7327>] ip_finish_output2+0x998/0xf00
[<00000000d309e9d3>] ip_output+0x1aa/0x2c0
[<000000007ecbd3a4>] tcp_transmit_skb+0x18db/0x3670
[<0000000042d2a45f>] tcp_write_xmit+0x4d4/0x58c0
[<0000000056a44199>] tcp_tasklet_func+0x3d9/0x540
[<0000000013d06d02>] tasklet_action+0x1ca/0x250
[<00000000fcde0b8b>] __do_softirq+0x1b4/0x5a3
[<00000000e7ed027c>] irq_exit+0x1e2/0x210
Fix it by adding the rest of the segments, if any, to skb
'to_free' list in that case.
Fixes: 6071bd1aa13e ("netem: Segment GSO packets on enqueue")
Signed-off-by: Alexey Kodanev <alexey.koda...@oracle.com>
---
net/sched/sch_netem.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/net/sched/sch_netem.c b/net/sched/sch_netem.c
index 7c179ad..a5023a2 100644
--- a/net/sched/sch_netem.c
+++ b/net/sched/sch_netem.c
@@ -508,8 +508,14 @@ static int netem_enqueue(struct sk_buff *skb, struct Qdisc
*sch,
1<<(prandom_u32() % 8);
}
- if (unlikely(sch->q.qlen >= sch->limit))
+ if (unlikely(sch->q.qlen >= sch->limit)) {
+ while (segs) {
+ skb2 = segs->next;
+ __qdisc_drop(segs, to_free);
+ segs = skb2;
+ }
return qdisc_drop(skb, sch, to_free);
+ }
qdisc_qstats_backlog_inc(sch, skb);
--
1.8.3.1
