Bug#858125: e1000: ethernet interface hangs occasionally, kernel reports hang

["Bruce Momjian,,," <bruce@momjian.us>]

On Tue, Mar 21, 2017 at 11:08:34PM -0400, Bruce Momjian,,, wrote:
> > The e1000e driver *does* have statistics for pause frames transmitted
> > and received (run: "ethtool -S eth0| grep flow_control").  If you log
> > these every second then it should be possible to see what happens
> > around the time the TX watchdog fires.  That could provide some clues
> > as to whether the NIC is behaving correctly.
> 
> OK, I am running this after setting flow control on/default on the
> switch and Debian, and rebooting:
> 
> 	daemon -- sh -c "while :; do date;ethtool -S eth0| grep flow_control;
> 	sleep 1;done > /root/ethtool"
> 
> I will report back with the relevant logging lines once it hangs again. 

OK, I have results of a hang after 24 hours of uptime.  The hangs are
listed here via dmesg -T:

	http://momjian.us/expire/eth0/dmesg.txt

showing the watchdog warning/hang/reset at 23:01 and port hang/reset at
23:10.

I have also produced the ethtool -S output every second for the entire
24-hour period, gziped, at:

	http://momjian.us/expire/eth0/ethtool.gz

You will see reception of a large number of rx_flow_control_xoff
messages about 50 minutes before the hangs, and just before the hangs.

-- 
  Bruce Momjian  <bruce@momjian.us>        http://momjian.us
  EnterpriseDB                             http://enterprisedb.com

+ As you are, so once was I.  As I am, so you will be. +
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