Unhandled exceptions in libcef.dll

[Kevin Sorber]

If I try to load a page that causes the browser to crash (like loading a huge amount of data via a RESTful call) the exception simply causes my application to shutdown. I have defined the AppDomain.CurrentDomain.UnhandledException and DispatcherUnhandledException events, but int this case they are not being called.  If I run it via the debugger at least the vhost32.exe catches it, but doesn't allow me to debug.  The information I do get in the "problem details" is below.  If I run the same page via Chrome I get the "Aw, Snap ... something went wrong" error page and If I use an awesomium based window I get their crash page.  In both of these examples the parent application is protected from the crash.  I don't need to recover the browser, but I  can't have the application shutting down for with no messages or logging.  Any suggestions would be appreciated.

Problem signature:

  Problem Event Name: APPCRASH

  Application Name: In2_Desktop.vshost.exe

  Application Version: 11.0.50727.1

  Application Timestamp: 5011d445

  Fault Module Name: libcef.dll

  Fault Module Version: 1.1364.1123.0

  Fault Module Timestamp: 5135c6a7

  Exception Code: 4000001f

  Exception Offset: 001fea33

  OS Version: 6.1.7601.2.1.0.256.48

  Locale ID: 1033

  Additional Information 1: 1159

  Additional Information 2: 11595227156776df5db14f98ce7b2079

  Additional Information 3: 1da5

  Additional Information 4: 1da5926164e4ad4dba962ef67e4629d9

[per.lu...@ecraft.com]

Hi,

You're right - this is definitely not good and something we should look into. The reason why you're not getting it through UnhandledException or DispatcherUnhandledException is because these only takes care of *managed* (i.e. .NET) exceptions. The error here is more likely thrown in the unmanaged/C++ realm which means that it must be handled there.

Can you reproduce this with the Visual Studio debugger attached? If so, please do the following: In your project settings, make sure that debugging of Unmanaged code is enabled (Project properties -> Application -> Debug -> Enable unmanaged code debugging, in VS2010 - may be slightly different in other versions).

Does this give you any hint whatsoever as to where in Cef/CefSharp the error occurs?

Best regards,

Per

[Kevin Sorber]

I can not get a libcef.dll.pdb to work inside my VS 2012 to give me symbols.  I can isolate it to a libcef.dll callstack location, but nothing more specific.  The way I generate the crash consistently is to call a server that returns a 100MB+ JSON result.  Obviously this would show something bad happening on the server, but I have seen the crash via other "normal" operations, but I'm not able to reproduce them on a regular basis.

Kevin

[per.lu...@ecraft.com]

Hi,

OK, but that's still better than nothing. What I think you should do is report this upstream, to the CEF project - especially if it can be reproduced with the "bare" cefclient.exe. (http://www.magpcss.net/cef_downloads/, take the latest cef1 .zip for Windows)

If you still get the exception with cefclient, it's a problem in CEF that would have to be addressed on their end (which feels a bit odd since Awesomium seems to take care of it...). If cefclient handles it somehow, we should look more carefully into how it does its stuff so we can improve the error handling on our end also.

Best regards,

Per

[kirred nel]

Hi,

I also get unhandled exceptions using CefSharp.WinForms.Example.exe (1.25.0), i think it says uncaught syntax error, expected end of input, when ever I try to browse either of these sites:

http://www.news24.co.za and http://www.bbc.com both redirect to alternate addresses dunno if that helps...

I also get the same crashes if I use the web view in a simple test app...

just downloaded the cefclient.exe and it also crashes on those sites....  eeeep

derrick

[per.lu...@ecraft.com]

Hi,

Please report it to the CEF project using this link: https://code.google.com/p/chromiumembedded/issues/list

(of course, check first if there might be any open issue addressing it already)

Best regards,

Per

[kirred nel]

Hi,

Reported it to the CEF project....and this is their reply......

Re: Unhandled Exceptions

by magreenblatt » Mon Jul 22, 2013 11:47 pm

If you're using CEF1 it's a known issue with flash. Use CEf3 instead.

CefSharp currently uses CEF1, if I'm not mistaken ? I saw a post about a CEF 3 preview, and I hoping that its got something to do with CefSharp and CEF3....

/*me*/... runs off to see....

Thanks

[Per Lundberg]

Hi,

OK, good to get it verified. We have started the project to migrating over to CEF3 but it's still probably a month or even some months before the first public beta version will be available. But be patient; you will get Chromium 27 also as an extra added bonus. :)

(for the time being, you can always try out the "cef3_2nd_attempt" branch in Github if you are brave. If it breaks, you get to keep both parts. ;)

Best regards,

Per