On Fri, May 11, 2018 at 12:08:33PM -0700, Eric Dumazet wrote: > > > On 05/11/2018 11:41 AM, Marcelo Ricardo Leitner wrote: > > > But calling ip6_xmit with rcu_read_lock is expected. tcp stack also > > does it. > > Thus I think this is more of an issue with IPv6 stack. If a host has > > an extensive ip6tables ruleset, it probably generates this more > > easily. > > > >>> sctp_v6_xmit+0x4a5/0x6b0 net/sctp/ipv6.c:225 > >>> sctp_packet_transmit+0x26f6/0x3ba0 net/sctp/output.c:650 > >>> sctp_outq_flush+0x1373/0x4370 net/sctp/outqueue.c:1197 > >>> sctp_outq_uncork+0x6a/0x80 net/sctp/outqueue.c:776 > >>> sctp_cmd_interpreter net/sctp/sm_sideeffect.c:1820 [inline] > >>> sctp_side_effects net/sctp/sm_sideeffect.c:1220 [inline] > >>> sctp_do_sm+0x596/0x7160 net/sctp/sm_sideeffect.c:1191 > >>> sctp_generate_heartbeat_event+0x218/0x450 net/sctp/sm_sideeffect.c:406 > >>> call_timer_fn+0x230/0x940 kernel/time/timer.c:1326 > >>> expire_timers kernel/time/timer.c:1363 [inline] > > > > Having this call from a timer means it wasn't processing sctp stack > > for too long. > > > > I feel the problem is that this part is looping, in some infinite loop. > > I have seen this stack traces in other reports.
Checked mail history now, seems at least two other reports on RCU stalls had sctp_generate_heartbeat_event involved. > > Maybe some kind of list corruption. Could be. Do we know if it generated a flood of packets? Marcelo
