[IFS] Divide error in IFSSaver::_Init(BRect)

[dexterkidd]

hrev47213.

After I installed some Chinese fonts: simsun, microsoft yahei, wqy zenhei, wqy bitmapsong in /boot/system/non-packaged/data/fonts/ and change haiku's appearance and WebPositive's main font I could not start ScreenSaver preference. Every time I get a crash when I open ScreenSaver.

[dexterkidd]

ScreenSaver crash dump

[diver]

From the crash report it looks like it's IFS screensaver which cause the crash. Could you attach your /boot/home/config/settings/ScreenSaver_settings?

[stippi]

I've looked at the code, but don't understand where it would divide anything in IFSSaver::_Init(BRect). The IFS constructor would not be inlined either, I believe. And if something confuses the locking code, I would think the real bug is not where it crashes.

[anevilyak]

Replying to stippi:

I've looked at the code, but don't understand where it would divide anything in IFSSaver::_Init(BRect). The IFS constructor would not be inlined either, I believe. And if something confuses the locking code, I would think the real bug is not where it crashes.

It's actually crashing in the IFS constructor, its symbol simply isn't properly demangled (__3IFSG5BRect + 0x2d6).

[korli]

It seems it happens ​here: we have a division by zero when the rect width and height are zero.

[stippi]

Yes. And thanks! Should be fixed in hrev47221. Of course, this only fixes symptoms. The fact remains that the rect is invalid, I didn't investigate that. I looked over the code in IFS to make sure it works properly when exiting the constructor early. I'll leave the ticket open, since I didn't test the change, and would like more feedback on what happens now.

[pulkomandy]

The rect is the bounds of the view passed to StartSaver. I guess the screensaver preview is started too early, before the view is layouted?

[stippi]

Sounds like a very likely scenario, indeed.

[jscipione]

Please retest in >= hrev47223, the crash should be fixed.

The views are laid out before the preview starts.

[HAL]

I tried hrev47223 and the bug is fixed.

[HAL]

It is fixed when Screensaver app is started with IFS previously selected but if Flurry is selected, starting ScreenSaver causes a very similar crash. I am not certain if it is the same. I have a debug from the crash. I will upload it if it looks the same.

[HAL]

Replying to HAL:

It is fixed when Screensaver app is started with IFS previously selected but if Flurry is selected, starting ScreenSaver causes a very similar crash. I am not certain if it is the same. I have a debug from the crash. I will upload it if it looks the same.

No I think this is a different bug: segment violation.

[diver]

Flurry issue is probably already being tracked in #10206. If the stack trace is different, please open a new ticket. This one is fixed in hrev47223.

[jessicah]

The fix only hides the issue. Affects many other screensavers (Gravity is an example).

[pulkomandy]

All screensavers fixed now.