netdev - Re: RCU callback crashes

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Wed, 20 Dec 2017 16:50:55 -0800
From:   Jakub Kicinski <kubakici@...pl>
To:     John Fastabend <john.fastabend@...il.com>
Cc:     Cong Wang <xiyou.wangcong@...il.com>,
        Jiri Pirko <jiri@...nulli.us>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>
Subject: Re: RCU callback crashes

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  }