** Description changed:

+ [impact]
+ 
+ The i40e driver sometimes causes a "malicious device" event that the
+ firmware detects, which causes the firmware to reset the nic, causing an
+ interruption in the network connection - which can cause further
+ problems, e.g. if the interface is in a bond; the reset will at least
+ cause a temporary interruption in network traffic.
+ 
+ [fix]
+ 
+ The upstream patch to fix this adjusts how the driver fragments TX data;
+ the "malicious driver" detected by the firmware is a result of
+ incorrectly crafted TX fragment descriptors (the firmware has specific
+ complicated restrictions on this).  The patch is from Intel, and they
+ suggested this specific patch to address the problem; additionally I
+ have checked with someone who reported this to me and provided a test
+ kernel with the patch to them, and they have been able to run ~6 weeks
+ so far without reproducing the issue; previously they could reproduce it
+ as quickly as a day, but usually within 2-3 weeks.
+ 
+ [test case]
+ 
+ the bug is unfortunately very difficult to reproduce, but as shown in
+ this (and previous) bug comments, some users of the i40e have traffic
+ that can consistently reproduce the problem (although usually on the
+ order of days, or longer, to reproduce).  Reproducing is easily
+ detected, as the nw traffic will be interrupted and the system logs will
+ contain a message like:
+ 
+ i40e 0000:02:00.1: TX driver issue detected, PF reset issued
+ 
+ [regression potential]
+ 
+ the patch for this alters how tx is fragmented by the driver, so a
+ possible regression would likely cause problems in TX traffic and/or
+ additional "malicious device detection" events.
+ 
+ 
+ [original description]
+ 
  This is a continuation from bug 1713553; a patch was added in that bug
  to attempt to fix this, and it may have helped reduce the issue but
  appears not to have fixed it, based on more reports.
  
  The issue is the i40e driver, when TSO is enabled, sometimes sees the
  NIC firmware issue a "MDD event" where MDD is "Malicious Driver
  Detection".  This is vaguely defined in the i40e spec, but with no way
  to tell what the NIC actually saw that it didn't like.  So, the driver
  can do nothing but print an error message and reset the PF (or VF).
  Unfortunately, this resets the interface, which causes an interruption
  in network traffic flow while the PF is resetting.
  
  See bug 1713553 for more details.

-- 
You received this bug notification because you are a member of Ubuntu
Bugs, which is subscribed to Ubuntu.
https://bugs.launchpad.net/bugs/1723127

Title:
  Intel i40e PF reset due to incorrect MDD detection (continues...)

To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1723127/+subscriptions

-- 
ubuntu-bugs mailing list
ubuntu-bugs@lists.ubuntu.com
https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs

Reply via email to