[Tutorial] Debugging (with breakpoints) on C series

[sectroyer]

• Unpack attached archive to /mtd_rwcommon/
• copy /mtd_rwcommon/gdb to some location from PATH variable
• add to your .gdbinit:

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  set libthread-db-search-path /mtd_rwcommon/debug/lib/
  set auto-load safe-path /mtd_rwcommon/debug/lib/

Breakpoints should now be working

[plasticassius]

Wow, this is exciting! I've tried to get gdb working, but never got very far. In order to try out your version of gdb, I thought I'd try to make a patch to allow media playback from an xfs format usb drive. However, I'm having some problems. Would you let me know if you can see problems with what I'm doing?

I started gdb with

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gdb /mtd_exe/exeDSP 61

After I did that, when I pressed MEDIA (or any other remote button), the led on the tv flash, but the button has no other effect. After, when I exit gdb with quit, the button has it's effect. Since the button doesn't seem to execute anything while gdb is running, I thought that exeDSP wasn't running. However, when I type 'run' to gdb, I get "The program being debugged has been started already." I want to place breakpoints to see what happens when I press MEDIA, but pressing MEDIA doesn't do anything when gdb is running.

[sectroyer]

Wow, this is exciting! I've tried to get gdb working, but never got very far. In order to try out your version of gdb, I thought I'd try to make a patch to allow media playback from an xfs format usb drive. However, I'm having some problems. Would you let me know if you can see problems with what I'm doing?

I started gdb with

Code: Select all

gdb /mtd_exe/exeDSP 61

After I did that, when I pressed MEDIA (or any other remote button), the led on the tv flash, but the button has no other effect. After, when I exit gdb with quit, the button has it's effect. Since the button doesn't seem to execute anything while gdb is running, I thought that exeDSP wasn't running. However, when I type 'run' to gdb, I get "The program being debugged has been started already." I want to place breakpoints to see what happens when I press MEDIA, but pressing MEDIA doesn't do anything when gdb is running.

You start gdb incorrectly you should use:

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gdb --pid 61

or even better:

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gdb --pid `pidof exeDSP`

[plasticassius]

Thanks, but it behaves the same when I start it the way you recommend.

[sectroyer]

Thanks, but it behaves the same when I start it the way you recommend.

I think you don't know how to use gdb After starting gdb program is HANGED. You nee to use:

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continue

command to resume it It's NORMAL tv doesn't react

[plasticassius]

Yes! Thanks! I ran continue and exeDSP became resposive! However, afterwards, the gdb prompt didn't reappear. I take it that only one of gdb or exeDSP runs at a time. Although, I'm getting messages from gdb about threads starting and exiting.

You're right that I don't have much experience with gdb, but I think that I'll be able to learn more about it now. My next step will be to try out breakpoints and watchpoints.