Comment 11 for bug 1766377

I discovered a way to cause this instantly, I attempted to change the size of the ring buffers from 512 bytes to the hardware maximum of 4096 using: ethtool -G eno1 rx 4096 tx 4096, it instantly hung the interface with the following in dmesg:

[458611.154752] e1000e 0000:00:19.0 eno1: Detected Hardware Unit Hang:
                  TDH <48>
                  TDT <73>
                  next_to_use <73>
                  next_to_clean <47>
                buffer_info[next_to_clean]:
                  time_stamp <11b5117a3>
                  next_to_watch <48>
                  jiffies <11b511d40>
                  next_to_watch.status <0>
                MAC Status <80083>
                PHY Status <796d>
                PHY 1000BASE-T Status <7c00>
                PHY Extended Status <3000>
                PCI Status <10>
[458613.138731] e1000e 0000:00:19.0 eno1: Detected Hardware Unit Hang:
                  TDH <48>
                  TDT <73>
                  next_to_use <73>
                  next_to_clean <47>
                buffer_info[next_to_clean]:
                  time_stamp <11b5117a3>
                  next_to_watch <48>
                  jiffies <11b512500>
                  next_to_watch.status <0>
                MAC Status <80083>
                PHY Status <796d>
                PHY 1000BASE-T Status <7c00>
                PHY Extended Status <3000>
                PCI Status <10>
[458615.122888] e1000e 0000:00:19.0 eno1: Detected Hardware Unit Hang:
                  TDH <48>
                  TDT <73>
                  next_to_use <73>
                  next_to_clean <47>
                buffer_info[next_to_clean]:
                  time_stamp <11b5117a3>
                  next_to_watch <48>
                  jiffies <11b512cc0>
                  next_to_watch.status <0>
                MAC Status <80083>
                PHY Status <796d>
                PHY 1000BASE-T Status <7c00>
                PHY Extended Status <3000>
                PCI Status <10>
[458617.106832] e1000e 0000:00:19.0 eno1: Detected Hardware Unit Hang:
                  TDH <48>
                  TDT <73>
                  next_to_use <73>
                  next_to_clean <47>
                buffer_info[next_to_clean]:
                  time_stamp <11b5117a3>
                  next_to_watch <48>
                  jiffies <11b513480>
                  next_to_watch.status <0>
                MAC Status <80083>
                PHY Status <796d>
                PHY 1000BASE-T Status <7c00>
                PHY Extended Status <3000>
                PCI Status <10>[458619.154912] e1000e 0000:00:19.0 eno1: Detected Hardware Unit Hang:
                  TDH <48>
                  TDT <73>
                  next_to_use <73>
                  next_to_clean <47>
                buffer_info[next_to_clean]:
                  time_stamp <11b5117a3>
                  next_to_watch <48>
                  jiffies <11b513c80>
                  next_to_watch.status <0>
                MAC Status <80083>
                PHY Status <796d>
                PHY 1000BASE-T Status <7c00>
                PHY Extended Status <3000>
                PCI Status <10>
[458620.562618] e1000e 0000:00:19.0 eno1: Reset adapter unexpectedly
[458620.562761] bridge0: port 1(eno1) entered disabled state
[458620.562789] bridge0: topology change detected, propagating
[458623.880650] e1000e: eno1 NIC Link is Up 1000 Mbps Full Duplex, Flow Control: Rx/Tx
[458623.880683] bridge0: port 1(eno1) entered blocking state
[458623.880688] bridge0: port 1(eno1) entered listening state
[458638.995031] bridge0: port 1(eno1) entered learning state
[458654.355381] bridge0: port 1(eno1) entered forwarding state
[458654.355385] bridge0: topology change detected, sending tcn bpdu
[476901.384610] bridge0: port 1(eno1) entered disabled state
[476901.384656] bridge0: topology change detected, propagating
[476905.544755] e1000e: eno1 NIC Link is Up 1000 Mbps Full Duplex, Flow Control: Rx/Tx
[476905.544788] bridge0: port 1(eno1) entered blocking state
[476905.544791] bridge0: port 1(eno1) entered listening state
[476920.887125] bridge0: port 1(eno1) entered learning state
[476936.247478] bridge0: port 1(eno1) entered forwarding state
[476936.247482] bridge0: topology change detected, sending tcn bpdu