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Last Post 07 May 2015 09:32 AM by  bradb
Ethernet packet storm overloads CPU processor
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Gary Baran
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Posts:5


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29 Apr 2015 07:36 AM
    Our product which utilizes the MIMX31BSOMCR SOM will cease to function if the ethernet connection receives a broadcast or multicast packet storm. It would appear that the CPU becomes overloaded. This happens in both Lolo and also while running a WinCE 5.0 image. Is there any resolve for this issue?
    Adam Ford
    Advanced Member
    Advanced Member
    Posts:754


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    29 Apr 2015 09:29 AM
    Gary,

    Can you give instructions to reproduce the packet storm you're using reproduce the problem in Lolo? Can you also tell me what version of Logic Loader you are using?

    adam
    Gary Baran
    New Member
    New Member
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    29 Apr 2015 11:45 AM

    Using Lolo version 2.4.12

    Connected controller with SOM to a non-managed ethernet switch (Netgear Model FS108). Create fatal loop by directly connecting two switch ports together with a patch cable. Power on controller and Lolo stops right after "Starting DHCP on sm0" instruction. 

    bradb
    Basic Member
    Basic Member
    Posts:196


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    30 Apr 2015 01:04 PM
    Gary,

     

    I have connected an i.MX31 SOM development kit a Netgear ProSAFE FS108 unmanaged switch as you described and followed these steps below.

     

    1.  Connected the Netgear FS108 switch to my LAN

    2.  Connected another port of the Netgear FS108 switch to an i.MX31 development kit baseboard with an i.MX31 SOM

    3.  Connected powered to the Netgear FS108 switch

    4.  Connect the fatal loop back between two ports on the Netgear FS108 switch with a patch cable

    5.  Powered on the i.MX31 development kit to boot Logic Loader 2.4.12

    6.  Entered "ifconfig sm0 dhcp" and noticed the system did not freeze.  There was an error stating no connected was made.  "error: ifconfig: unable to get ip address; still trying (sm0)"

    7.  Later removed the fatal loop back between the two ports and resubmitted the "ifconfig sm0 dhcp" command again.  Here I was able to get an IP address.  "Obtaining DHCP on sm0 ....."

     Below is a link to the log file. 

     i.MX31_boot_w_fatal_loop.log.txt

    Have you tried testing this using an i.MX31 development kit in your environment?


    Regards,

    Brad



    Gary Baran
    New Member
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    Posts:5


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    30 Apr 2015 03:20 PM

    Unfortunately the development got lost in a office move many years ago, so I do not currently have it to test.

    Gary Baran
    New Member
    New Member
    Posts:5


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    01 May 2015 03:33 PM

    Today I was able to re-acquire a Logic i.MX31 Development kit and rerun the same tests on the development kit. The development kit had Lolo version 2.4.0, slightly earlier version than our production units (Lolo 2.4.12) although I had no problem in consistently reproducing the problem. 

    1) Connected the development kit ethernet port to a powered non-managed switch (Netgear FS108).

    2) Created a fatal loop on the ethernet switch by directly connecting two of the switches ports together with a patch cable.

    3) Connected a serial connection to a PC running TeraTerm.

    4) Powered on the developement kit and instantly exited the configuration script by pressing "Q".

    5) At the Losh prompt entered "ifconfig sm0 dhcp".

    6) As the echo "Starting DHCP on sm0.." is received, Lolo appears to freeze at this point and a high activity can be observed on the ethernet switch communication leds. 

    7) The TeraTerm output below shows two tests that were ran. The first test is without the fatal loop connected. The first test responds as expected with a "error: ifconfig: unable to get ip address; still trying (sm0)" message.  For the second test, the fatal loop was connected prior to powering on the development kit. Once the losh command "ifconfig sm0 dhcp" was entered, the development kit remained at the "Starting DHCP on sm0 .." message for at least 5 minutes. My assumption is that the DHCP function sends out a broadcast message which gets trapped in a switch loop and causes a broadcast storm. This broadcast storm causes excessive interrupts that overload the CPU. Our main concern is not with Lolo but that this same condition happens during normal operation in the WinCE 5.0 operating system.

     

                             LogicLoader

     (c) Copyright 2002-2006, Logic Product Development, Inc.
     All Rights Reserved.
     Version 2.4.0-IMX31_10 0001
    *****************************************************************

    losh> ifconfig sm0 dhcp
    Starting DHCP on sm0 ..........
    error: ifconfig: unable to get ip address; still trying (sm0)
    losh> }}
    *****************************************************************

                             LogicLoader

     (c) Copyright 2002-2006, Logic Product Development, Inc.
     All Rights Reserved.
     Version 2.4.0-IMX31_10 0001
    *****************************************************************

    losh> ifconfig sm0 dhcp
    Starting DHCP on sm0 ..

     

     

     

    bradb
    Basic Member
    Basic Member
    Posts:196


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    04 May 2015 08:31 AM

    Gary,

    I was able to verify that the i.MX31 SOM does become unresponsive due to the broadcast storm using the steps provided above while leaving the non-managed Netgear FS108 switch isolated from the network.  Broadcast storms was not consider as a test case during the development of Logic Loader or the WinCE Ethernet driver.   Both Logic Loader and the WinCE release have been considered maintenance releases for a while.  Only significant issues that affects many customers or updates required due to changes in hardware are being considered for future releases.  An recently released EOL notice shows the last time buy for all i.MX31 SOMs will be September 30, 2015.

    Customers looking for improvements outside the scope of a maintenance release are encouraged to 
    contract us for development assistance from our Product Development Services team.   Click here to submit your request.   Someone will contact you as soon as possible.

    Regards,
    Brad

    Gary Baran
    New Member
    New Member
    Posts:5


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    05 May 2015 02:30 PM

    Brad,

    Thanks for your time and insight into this issue. Unfortunately this is not the resolution that we were looking for.  Our company has been producing a product with this SOM for many of years and we currently have a considerable installed base. We have become aware of this issue via problems that our customers have reported. The reliable operation of our machinery with utilizes this SOM is vital to our customers operation. The significance of this issue is certainly critical to those who have experienced it and the number affected could potentially be every application with an Ethernet connection. I certainly hope that your organization will consider the potential severity of this issue, and resolve this as a maintenance item. 

    bradb
    Basic Member
    Basic Member
    Posts:196


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    07 May 2015 09:32 AM
    Gary,

    At this time this problem is not believed to be related to an issue or limitation of the i.MX31 SOM but is related to the reference software provided for the i.MX31 SOM. Since there was not a requirements to test against a broadcast or multicast packet storm event in the initial SRD it does appear this issue has not yet been addressed.

    A reference BSP is provided to help our customers get to market more quickly. The referenced BSPs are created to provide many of the most common drivers and tested against most common usage models at the time of development. Logic PD provides additional development services for features not covered in the standard BSP release under a contract.

    I have reached out to my management and they agree we can still provide additional development assistance under a contract even though the i.MX31 is considered EOL. Let us know if we can further assistance.

    Thanks,
    Brad
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