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Bug #5770

open

simtrace2 firmware ignores any but the first USB message sent by simtrace2-list after a reset

Added by laforge 15 days ago. Updated 7 days ago.

Status:
Feedback
Priority:
Normal
Assignee:
Category:
firmware
Target version:
-
Start date:
11/14/2022
Due date:
% Done:

0%

Spec Reference:

Description

The simtrace2 firmware appears to have a problem (probably a race condition of some sort, with the USB stack) where it accepts the first USB message sent by simtrace2-list after a reset, but then ignores others. During investigation, it was noticed that when sending two commands in a row from a single instance of simtrace2, the first is ignored, and the second is processed.

So, in https://gerrit.osmocom.org/c/simtrace2/+/26864 a hack was put into `simtrace2-tool` so that it sends a fake, empty, error message, to kick the remote SIM firmware into accepting the second, real message. The strange thing is, that when you send two messages like this, it has the side effect of keeping the processor from getting stuck.

So, something about sending two messages has two effects 1.) it kicks the SIM firmware, if it is stuck, and 2.) prevents the SIM firmware from getting stuck in the first place.

Actions #1

Updated by laforge 15 days ago

  • Status changed from New to Feedback
  • Assignee set to jtavares

Can you please provide some more information on how to reproduce this? Like a step-by-step guide how the problem is reproduced (or how it is not reproduced)?

I somehow feel a bit reminded to https://osmocom.org/issues/4329 but that was fixed long ago...

Actions #2

Updated by jtavares 7 days ago

laforge wrote in #note-1:

Can you please provide some more information on how to reproduce this? Like a step-by-step guide how the problem is reproduced (or how it is not reproduced)?

I somehow feel a bit reminded to https://osmocom.org/issues/4329 but that was fixed long ago...

I also saw your note in Gerrit to see if https://gerrit.osmocom.org/c/simtrace2/+/16910 might fix this issue. I will look into this eventually, but I cannot commit to a particular timeframe since this is a low-priority issue for me right now, given that my "empty message" workround is keeping us running at the moment. But, I would like to get to root cause, and your description in https://gerrit.osmocom.org/c/simtrace2/+/16910 seems similar to what I was seeing.

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