2010-09-17 02:43:26     Let's hang up uClinux

Document created by Aaronwu Employee on Aug 22, 2013
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2010-09-17 02:43:26     Let's hang up uClinux

Peter Gombos (HUNGARY)

Message: 93526   




Let me describe a simple way to hang up uClinux 2009R1.1RC4


You need a simple ethernet switch (I used an 8 port Linksys SOHO switch, unmanaged), 2 pcs UTP patch cable and the device running uClinux. Connect the device to the switch port 1. Now make a loop connecting port 2 to port 3. From the serial console try to ping any station. At this point uClinux send out an ARP reguest to get the MAC address of the station. The ARP request is a broadcast message. The switch sends out the broadcast to all ports. Because of the loop the sent broadcast received again and send it again. So the uClinux receives ethernet packets with full speed.


During this stage the linux stops. The real time clock doesn't count. If I disconnect the loop within seconds linux able to continue normal operation but sometimes not. If you keep the loop more than 20 seconds the watchdog resetting the system.


I know it is not a normal operation but as far as I see heavy network traffic sometimes resets my board.


This test made with our custom board with custom firmware based on 2009R1.1RC4. I see significant changes in 2010R1, thats why I hope this misbehavior disappeared.


Would somebody reproduce this and compare 2009 to 2010?




2010-09-17 02:47:34     Re: Let's hang up uClinux

Mike Frysinger (UNITED STATES)

Message: 93527   


you didnt describe your hardware at all ...




2010-09-17 04:19:00     Re: Let's hang up uClinux

Peter Gombos (HUNGARY)

Message: 93551   




Our board is very similar to ADSP-BF537 EZ-KIT LITE. Same RAM type, same PHY, 3xM25P128 SPI flash, Hitachi TX-09 TFT with AD7877 touchscreen.