Sure, but after catching the stacktrace. On середа, 6 січня 2016 р. 10:43:45 EET Yuchung Cheng wrote: > Could you turn off ecn (sysctl net.ipv4.tcp_ecn=0) to see if this still > happen?
> >> On December 22, 2015 4:10:32 AM EET, Yuchung Cheng <ych...@google.com> wrote: > >> >On Mon, Dec 21, 2015 at 12:25 PM, Oleksandr Natalenko > >> > > >> ><oleksa...@natalenko.name> wrote: > >> >> Commit 3759824da87b30ce7a35b4873b62b0ba38905ef5 (tcp: PRR uses CRB > >> > > >> >mode by > >> > > >> >> default and SS mode conditionally) introduced changes to > >> > > >> >net/ipv4/tcp_input.c > >> > > >> >> tcp_cwnd_reduction() that, possibly, cause division by zero, and > >> > > >> >therefore, > >> > > >> >> kernel panic in interrupt handler [1]. > >> >> > >> >> Reverting 3759824da87b30ce7a35b4873b62b0ba38905ef5 seems to fix the > >> > > >> >issue. > >> > > >> >> I'm able to reproduce the issue on 4.3.0–4.3.3 once per several day > >> >> (occasionally). > >> >> > >> >> What could be done to help in debugging this issue? > >> > > >> >Do you have ECN enabled (i.e. sysctl net.ipv4.tcp_ecn > 0)? > >> > > >> >If so I suspect an ACK carrying ECE during CA_Loss causes entering CWR > >> >state w/o calling tcp_init_cwnd_reduct() to set tp->prior_cwnd. Can > >> >you try this debug / quick-fix patch and send me the error message if > >> >any? > >> > > >> >> Regards, > >> >> > >> >> Oleksandr. > >> >> > >> >> [1] http://i.piccy.info/ > >> > > >> >i9/6f5cb187c4ff282d189f78c63f95af43/1450729403/283985/951663/panic.jpg > >> > >> -- > >> Sent from my Android device with K-9 Mail. Please excuse my brevity. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
