Re: [microblaze-uclinux] hang of user app on its startup (bad ima ge file because of a tool chain bug?)

[John Williams <jwilliams@xxxxxxxxxxxxxx>]

Hi Falk,

I haven't seen anything like this before - see below for some
comments/questions

Brettschneider Falk wrote:

>>Often my user app doesn't start, better to say it hangs 
>>before reaching the
>>main() function.

Is it just the app that hangs, or does it lock up the kernel as well?

>>I compile and link the program with mb-gcc 3.4.1 (Xilinx EDK 8.1 Build
>>EDK_I.15 290805) on SuSE-Linux and generate the image this way:
>>  mb-flthdr -z -o ...
>>  zflat ...


>>After that I put it in Linux' romfs/bin and start it out of 
>>the uclinux
>>startscript on Linux boot-up.

Do you see any different behaviour if you start it from the console /
command line?

>>First I suspected the filesizes of my user app to be not 
>>aligned or such
>>things. Here's a list of program sizes (in bytes) I had, '!' 
>>means that it
>>hung:
>>296059 !
>>296053 !
>>296356
>>296205 !
>>296160
>>288998
>>294000
>>294003 !
>>297219
>>297236
>>298160
>>298389
>>300408 !
>>300601
>>
>>The strange thing is, in case that it hangs I just have to 
>>comment out or in
>>any little C sourcecode and after recompiling it starts up normally.
>>Usually, I just comment out a little printf call. I'm sure I 
>>don't have a
>>stack overflow but it shouldn't matter anyway since it hangs 
>>before reaching
>>the main loop. Maybe it's interesting that I have some global struct
>>instances in the program but actually not huge ones.

Do you have any global variables across multiple source files, maybe
declared with extern?

Have you confirmed that your auto-config.in settings (esp. regarding
MUL/SHIFT/DIV) match the CPU correctly?

Are you able to reduce it down to a minimal test case?

I've built and run uClinux apps well over 1Mbyte, so it's not the total
file size that should be a problem...

As a last resort, if you tell us what combination of hard mul/div/shift
etc you have, perhaps post the binary (working and non-working) and
someone can try it?

Hope this helps,

John

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