On Wed, 20 Dec 2017 16:41:14 -0800, Jakub Kicinski wrote:
> Just as I hit send... :) but this looks unrelated, "Comm: sshd" -
> so probably from the management interface.
>
> [ 154.604041]
> ==================================================================
> [ 154.612245] BUG: KASAN: slab-out-of-bounds in
> pfifo_fast_dequeue+0x140/0x2d0
> [ 154.620219] Read of size 8 at addr ffff88086bb64040 by task sshd/983
> [ 154.627403]
> [ 154.629161] CPU: 10 PID: 983 Comm: sshd Not tainted
> 4.15.0-rc3-perf-00984-g82d3fc87a4aa-dirty #13
> [ 154.639190] Hardware name: Dell Inc. PowerEdge R730/072T6D, BIOS 2.3.4
> 11/08/2016
> [ 154.647665] Call Trace:
> [ 154.650494] dump_stack+0xa6/0x118
> [ 154.654387] ? _atomic_dec_and_lock+0xe8/0xe8
> [ 154.659355] ? trace_event_raw_event_rcu_torture_read+0x190/0x190
> [ 154.666263] ? rcu_segcblist_enqueue+0xe9/0x120
> [ 154.671422] ? _raw_spin_unlock_bh+0x91/0xc0
> [ 154.676286] ? pfifo_fast_dequeue+0x140/0x2d0
> [ 154.681251] print_address_description+0x6a/0x270
> [ 154.686601] ? pfifo_fast_dequeue+0x140/0x2d0
> [ 154.691565] kasan_report+0x23f/0x350
> [ 154.695752] pfifo_fast_dequeue+0x140/0x2d0
If we trust stack decode it's:
615 static struct sk_buff *pfifo_fast_dequeue(struct Qdisc *qdisc)
616 {
617 struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
618 struct sk_buff *skb = NULL;
619 int band;
620
621 for (band = 0; band < PFIFO_FAST_BANDS && !skb; band++) {
622 struct skb_array *q = band2list(priv, band);
623
>> 624 if (__skb_array_empty(q))
625 continue;
626
627 skb = skb_array_consume_bh(q);
628 }
629 if (likely(skb)) {
630 qdisc_qstats_cpu_backlog_dec(qdisc, skb);
631 qdisc_bstats_cpu_update(qdisc, skb);
632 qdisc_qstats_cpu_qlen_dec(qdisc);
633 }
634
635 return skb;
636 }
