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Old 01-17-2010, 10:51 PM   #1
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Require help in debugging Signal 9 issue


I am currently running Linux 2.6.18 kernel on ARM9 which has some application ported for sensor management. When i run my stack as mentioned in the below test, it crashes generating "SIGNAL 9" error.

My sensor management stack on startup invokes Process "A" which in turn creates lot of Processes (B, C, D etc..) for managing different modules on my board basically targeted at monitoring different sensors, board interface like LAN, Serial, etc.. When i turn off the power and turn on the power repeatedly, i see Process "A" gets SIGNAL 9 because one of the child got terminated and due to which Process "A" restarts (restarting process is part of my app algorithm). As it restarts, whole of sensor logic goes for a toss leading to unexpected behavior. I am stuck on this issue for a long time and have hit road block...

1. Firstly FW is running from SPI flash
2. As soon as my Linux kerenel starts, it would launch my app, so do i need to use ulimit before starting the main app which spans many other process?
3. How do we find which process generated SIGNAL 9?
4. Is their any way it can be avoided?
5. When the crash happens, can i get some debug log?
6. Any other suggestion would be helpful...

PS: I am having problem runnin gdb so this solution is ruled out

Old 01-17-2010, 11:05 PM   #2
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Hi -

Suggestion: install a sigaction()" signal handler; this should give you the sender's PID:

ALSO: You absolutely, positively, without a doubt need a reliable debugger (e.g. gdb). If Gdb doesn't work yet ... then get it (or a reasonable substitute) working. You *are* going to find bugs (like this one) ... and you're going to be more or less helpless without a good debugger. Please make it an urgent priority - you'll project will be much happier.

Old 01-24-2010, 11:01 PM   #3
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Thanks for the suggestion...

As far as i know we won't be able to catch SIGNAL 9 (as it boils down to SIGKILL), neither install a SIGNAL handler... when i Googled, i found the same info... correct me if i am wrong or if you have w link wherein they explain how to trap SIGNAL 9, it would be of great help...



debugging, embedded, linux, signal

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