Ignoring the annoying SIG32 signal when debugging SPDK apps in QtCreator

Well I don’t know if I am doing something wrong but, every time I close down an app using SPDK being debugged via QtCreator, SIG32 gets trapped and pauses execution rather than cleaning up and exiting. It’s easy to suppress the pop-up window but I couldn’t work out how to avoid trapping the signal entirely. Fortunately I found this post which has the solution.

Basically, you open up the Options window and select Debugger. Then select the GDB tab. Within that, there’s a window for Additional Startup Commands. Within that window, add the line:

handle SIG32 pass nostop noprint

Then press Apply and Ok. From now on, the app won’t get hung up if this signal is generated on exit.

Debugging DPDK and SPDK applications in QtCreator: the root issue

There doesn’t seem to be any easy way to get SPDK and DPDK to work without root permission (ok, there is a way but this technique works for these and other things). Not impossible to deal with when running code but it does present a problem when debugging with QtCreator (or any other IDE that directly calls the debugger). There is a trick that allows gdb to be run with root permission without requiring a password (largely as described here).

sudo visudo

and add this line at the bottom of the file:

<username> ALL=(root) NOPASSWD:/usr/bin/gdb

where <username> is the appropriate user name. Now all that’s needed is to call sudo gdb instead of gdb. This can be done by creating a simple executable script called sudo-gdb containing:

sudo gdb $@

QtCreator then needs to know to use this version of the debugger. Go to Tools -> Options and select Kits. Select the Debugger tab and click on Add. Enter the full path to the new script. Then click on the Kits tab and select the new debugger in the Debugger drop-down and then click on Ok.

Yes, I should probably do it with the permissions trick and I will. One day.