That is correct, I have net.ipv4.tcp_ecn set to 1. I've recompiled the kernel with proposed patch, now still waiting for issue to be triggered.
Could I manually simulate the erroneous TCP ECN behavior to speed up the debugging? On понеділок, 21 грудня 2015 р. 18:10:32 EET Yuchung Cheng 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 -- 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
