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Author Topic: BRX Losing Password Configuration.  (Read 10154 times)

JeffS

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BRX Losing Password Configuration.
« on: October 05, 2023, 01:03:29 PM »
We have a BRX running firmware 2.9.6 that keeps losing it's password configuration.  Attached is the system log txt file.  You can see how it initially had an administrator account, then lost it, and we added it back shown as the default user updating the password configuration.  This has happened on this PLC 3-4 times now, and could be linked to the watchdog hardware timeouts https://forum.hosteng.com/index.php?topic=3849.0 , or possibly unrelated but definitely an issue.  Was this a bug with firmware 2.9.6 though not all PLCs running this firmware are showing this same behavior.

JeffS

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Re: BRX Losing Password Configuration.
« Reply #1 on: October 11, 2023, 02:20:18 PM »
So I updated this PLC to 2.9.7 firmware and it is still losing the password configuration.  The PLC program is intact, but the PW config only has the default user.  It did this after 11 $watchdogreboots since the last time it lost the password configuration, 3 watchdogreboots after updating to 2.9.7.

BobO

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Re: BRX Losing Password Configuration.
« Reply #2 on: October 11, 2023, 05:34:28 PM »
So I updated this PLC to 2.9.7 firmware and it is still losing the password configuration.  The PLC program is intact, but the PW config only has the default user.  It did this after 11 $watchdogreboots since the last time it lost the password configuration, 3 watchdogreboots after updating to 2.9.7.

The password config is stored in flash. It would be pretty hard to lose that unintentionally and not blow away other important things in flash.

You aren't inadvertently restoring an SD card based system image are you? I've done that before.
"It has recently come to our attention that users spend 95% of their time using 5% of the available features. That might be relevant." -BobO

JeffS

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Re: BRX Losing Password Configuration.
« Reply #3 on: October 11, 2023, 06:05:33 PM »
This BRX doesn't have a SD card installed, and I am not doing anything different with it than I do any of our other BRX PLCs.  I just write the program, I don't create and PLC register images or use any.    On this BRX in particular I haven't actually loaded a new program since 2022.

The only thing I have done is remotely put the PLC back into run when it drops out of run, and on Monday I updated the firmware.  It has lost the password config 3 times before updating firmware(Nov 2022 - Oct 9 2023), and once after updating firmware.   It has had 3 watchdogreboots since the firmware update, and 52 watchdogreboots since Nov 22 2022.

BobO

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Re: BRX Losing Password Configuration.
« Reply #4 on: October 11, 2023, 09:12:21 PM »
This BRX doesn't have a SD card installed, and I am not doing anything different with it than I do any of our other BRX PLCs.  I just write the program, I don't create and PLC register images or use any.    On this BRX in particular I haven't actually loaded a new program since 2022.

The only thing I have done is remotely put the PLC back into run when it drops out of run, and on Monday I updated the firmware.  It has lost the password config 3 times before updating firmware(Nov 2022 - Oct 9 2023), and once after updating firmware.   It has had 3 watchdogreboots since the firmware update, and 52 watchdogreboots since Nov 22 2022.

I don't know of any way for flash to be randomly changed, and as far as I know, this is the only report of this problem. Since you are also getting recurrent watchdogs, it's reasonable to assume the two are related. So...why?

Password config is stored in the same block of flash as some of the HEI setup data...like Node Number, Node Name, Description, and IP Setup. If something was setting those fields when the PLC watchdogged, the password config could easily get lost. I would have to dig into the code to evaluate the risk, but presumably the SETUPIP and SETUPNOD instructions could do the same thing.

Any chance something on the network is setting any of those fields and/or is one of those two instructions running at some interval?
"It has recently come to our attention that users spend 95% of their time using 5% of the available features. That might be relevant." -BobO

JeffS

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Re: BRX Losing Password Configuration.
« Reply #5 on: October 12, 2023, 07:31:15 PM »
So turns out I had a bug in the program for the last 2 years that caused the SETUPIP to execute once a minute.  It appears that after enough of these it causes the OS to crash, my guess based on your comments is that occasionally I am unlucky and the crash happens during the flash writing operation and the PW config is lost.  At least that is my assumption.   

I tested this by having the instruction fire once per second and I very consistently crash the OS after 1408 seconds.  Each time it did this I also lost the password configuration.  Figured this might be useful for you to see what exactly is happening to cause the OS to crash after writing the IP stuff 1408 times.  Related thread: https://forum.hosteng.com/index.php?topic=3849.0

What is interesting is that it doesn't affect the H2 Do-more this same way as those are operating in the field without a hitch even saddled with this bug.  That or they are on older firmware(many on 2.7.5) that may not be affected for some reason.