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Intermittent crash on IIS and IISExpress

Jun 10, 2016 at 1:07 PM
Edited Jun 10, 2016 at 1:30 PM
I have a weird issue, ClearScript sometimes crashes the application pool when
used intensively in my web application.

I got a dump file and opened it in Visual Studio but I'm missing the symbols file
ClearScriptV8-32.pdb to see a proper StackTrace and report something useful.

I'm currently using the nuget package, I'd like to avoid seting up the build on my computer to generate a pdb (I never built C++ projects on this computer, will probably need some installs...), could someone with the build already set up send this pdb to me (for the v5.04.6.0) ?

Jun 10, 2016 at 1:45 PM

The symbol file may not be useful unless it matches the assembly precisely. It would have to have been generated from the same source code and with the same compiler version, identical options, etc. Therefore it would make sense to contact the NuGet package owners for a copy of the file.

V8 issues can also be difficult to diagnose without a debug build of V8, so setting up a ClearScript/V8 build environment might be worthwhile.

In the meantime, can you somehow share your dump file?

Jun 10, 2016 at 3:04 PM

Thank you for your answer.
I was wondering the same thing about the pdb but unfortunately I failed to build v8 (the build script reports a failed step but there's no other information).
I'll try to look more into it monday.
The dump file is pretty large (800mb): you can grab it here:

Thank you in advance
Jun 12, 2016 at 8:34 AM
HI guillaume,

this might be the same issue that we are getting - but only with versions of ClearScript after 5.4.3. Could you try and see if you get the same issue after downgrading?
Jun 13, 2016 at 9:00 AM

I'm trying the downgrade, thanks for the tip.
Jun 13, 2016 at 9:55 AM
HI again Andrea,

It looks like it works, thanks a lot.
I'll not be 100% sure before letting my app run for few days but my attempts to manually trigger the issue do not work on that version, seems good.

I hope this information will also help the devs to find the origin of the issue.
Jun 15, 2016 at 12:14 AM
Hi guillaume86,

Thanks for sharing your crash dump! Although we couldn't symbolize most of the crash stack without matching PDBs, a VCRT symbol at the very top provided a strong clue. We'll post a potential fix within a few days. Unfortunately, since we can't reproduce your crash, we won't be able to verify the fix.

Thanks again!
Jun 15, 2016 at 8:39 AM

I'll run your new version locally to confirm (at 99%) that the problem is gone, and if not I'll try again to build it myself to provide the call stack.
Unfortunately I was unable to isolate the issue in a small project to share the crashing code easily (still have no idea what is triggering it).
Jun 20, 2016 at 7:34 PM
Hi guillaume86,

A potential fix has been posted here. Please give it a try if you get a chance.

Aug 23, 2016 at 2:46 PM
We are having IIS crashes on 5.4.6 NuGet package as well. We are trying the downgrade to 5.4.3. If someone can build a Nuget with the patch we can also try it. Or tell us the proper way to compile ClearScript and V8 like how the Nuget package is created and we can try that...

Aug 23, 2016 at 3:42 PM
Hi Bill,

We can't help you with the NuGet package, so we encourage you to consider building ClearScript yourself via the procedure in the ReadMe. The Git repository on this site includes a potential fix for the intermittent crashing issues you're seeing.

Good luck!
Sep 4, 2016 at 1:20 AM
We compiled this fix:

We tried it for a few hrs and it was MUCH better! Like night and day. We will have it 100% live next Thursday.
Sep 6, 2016 at 11:17 AM
Hi ClearScript team,

do you know when we can expect to see the fix in the latest released version?

Sep 6, 2016 at 2:11 PM
We tried it for a few hrs and it was MUCH better! Like night and day. We will have it 100% live next Thursday.

That's great to hear. Thanks for following up!
Sep 6, 2016 at 2:56 PM
do you know when we can expect to see the fix in the latest released version?

We're readying version 5.4.7 now, and it should be out within a week. It's a relatively small update.

One word of caution: Like most ClearScript releases, 5.4.7 is paired with a newer version of V8 than its predecessor, and as V8 is constantly undergoing rapid change, comprehensive application testing prior to deployment is advisable. In the meantime, it may make sense to deploy a locally-built copy of 5.4.6 with the fix.

Good luck!