Segfault if user_text_format doesn't contain any expansion tokens

[inferiorhumanorgans]

Using either the default %hostname or an explicitly specified value with an expansion token (e.g. %fps) works. If a value is specified in prudynt.cfg that doesn't contain a token prudynt will eventually crash when OSD::set_text calls IMP_OSD_UpdateRgnAttrData.

Typical dmesg output looks like:

[38003.835031] do_page_fault() #2: sending SIGSEGV to p2 for invalid read access from
[38003.835031] 00000002
[38003.835054] epc = 76f77bc8 in libc.so[76f0c000+b8000]
[38003.835087] ra  = 76ebf634 in libimp.so[76dfc000+107000]

[gtxaspec]

@inferiorhumanorgans thanks for digging in to this.

@Lu-Fi do you know if you fixed this in your new OSD branch? It's time to bring it in soon =D

[Lu-Fi]

@inferiorhumanorgans
i try to reproduce this, how often does it come up ?

[inferiorhumanorgans]

It'll crash 100% of the time anywhere from a few seconds to half an hour from when prudynt was started. With the default text of %hostname it's been up for a couple days without incident.

The only other thing I can think of is that I'm building this on an ARM box with the toolchain from make sdk.

[m4mmon]

hi,
I don't want to be too optimistic, but #86 might have solved this one.