Bug 175243 – REGRESSION (iOS 11 beta 3): Microsoft Power BI crashes

• Component: WebCore Misc.
• Status: RESOLVED WORKSFORME

Created attachment 317360 [details]
5 different crashes in WebCore

Hi.

Since iOS 11 beta 3 came out, we've started to get crashes during a login flow involving UIWebView with a password box.
Our app also has several WKWebViews preloaded and kept in memory for future use.
We don't get these crashes when the WKWebViews aren't loaded (no loadRequest is called)

Attached here is a ZIP with 5 crash examples (we get different ones). The crash usually happens when moving out of a password box and tapping a button.

Main Thread stack traces tops:
- WebCore::RenderBox::scrollPosition()
- WebCore::RenderLayer::hitTestList
- WebCore::LayoutState::LayoutState

Web Thread stack traces tops:
- WebCore::FontRanges::fontForFirstRange() (crash on overflow)
- WebCore::RenderBlockFlow::estimateLogicalTopPosition

Would appreciate your help.

Thanks!

[Alexey Proskuryakov]

Does this crash in a more interesting way when using GuardMalloc or ASan (especially an ASan build of WebKit)?

[Radar WebKit Bug Importer]

<rdar://problem/33779404>

[Simon Fraser (smfr)]

Best way to avoid these crashes would be to migrate to WKWebView.

Looks like iOS 11 beta 5 handled all issues and I don't see these crashes anymore.

I'll file another bug in case something pops up in future versions.

Thanks!

[Alexey Proskuryakov]

Thank you for following up!