Last Comment Bug 830765 - Multi-second hang during CollectNewLoadedModules
: Multi-second hang during CollectNewLoadedModules
Product: Core
Classification: Components
Component: Widget: Win32 (show other bugs)
: Trunk
: x86_64 Windows 7
-- normal (vote)
: mozilla21
Assigned To: :Ehsan Akhgari
: Jim Mathies [:jimm]
Depends on:
Blocks: 524944
  Show dependency treegraph
Reported: 2013-01-15 07:08 PST by Vladan Djeric (:vladan)
Modified: 2013-01-26 10:22 PST (History)
5 users (show)
See Also:
Crash Signature:
QA Whiteboard:
Iteration: ---
Points: ---
Has Regression Range: ---
Has STR: ---

Remove the unneeded code (6.55 KB, patch)
2013-01-15 09:56 PST, :Ehsan Akhgari
jonas: review+
lukasblakk+bugs: approval‑mozilla‑aurora+
lukasblakk+bugs: approval‑mozilla‑beta-
Details | Diff | Splinter Review

Description User image Vladan Djeric (:vladan) 2013-01-15 07:08:37 PST
I noticed a 5 second main-thread hang with the following stack:

NtWaitForSingleObject (in wntdll.pdb)
RtlpDeCommitFreeBlock (in wntdll.pdb)
LdrQueryModuleInfoLocalLoaderLock (in wntdll.pdb)
RtlQueryProcessModuleInformation (in wntdll.pdb)
RtlQueryProcessDebugInformation (in wntdll.pdb)
ThpCreateRawSnap (in wkernel32.pdb)
CreateToolhelp32Snapshot (in wkernel32.pdb)
CollectNewLoadedModules (in xul.pdb)
nsAppShell::ProcessNextNativeEvent(bool) (in xul.pdb)
nsBaseAppShell::OnProcessNextEvent(nsIThreadInternal *,bool,unsigned int) (in xul.pdb)
nsThread::ProcessNextEvent(bool,bool *) (in xul.pdb)
mozilla::ipc::MessagePump::Run(base::MessagePump::Delegate *) (in xul.pdb)
MessageLoop::RunHandler() (in xul.pdb)
MessageLoop::Run() (in xul.pdb)
nsBaseAppShell::Run() (in xul.pdb)
nsAppShell::Run() (in xul.pdb)
nsAppStartup::Run() (in xul.pdb)
XREMain::XRE_mainRun() (in xul.pdb)
XREMain::XRE_main(int,char * * const,nsXREAppData const *) (in xul.pdb)
XRE_main (in xul.pdb)
do_main (in firefox.pdb)
wmain (in firefox.pdb)
__tmainCRTStartup (in firefox.pdb)
BaseThreadInitThunk (in wkernel32.pdb)
__RtlUserThreadStart (in wntdll.pdb)
_RtlUserThreadStart (in wntdll.pdb)

This stack is also a frequent chrome-hang. Can we make the CreateToolhelp32Snapshot call off the main thread?
Comment 1 User image :Ehsan Akhgari 2013-01-15 09:56:06 PST
Created attachment 702393 [details] [diff] [review]
Remove the unneeded code
Comment 2 User image Jonas Sicking (:sicking) No longer reading bugmail consistently 2013-01-17 22:51:24 PST
Comment on attachment 702393 [details] [diff] [review]
Remove the unneeded code

Review of attachment 702393 [details] [diff] [review]:

Yes! I don't believe we ever had use for this code. Definitely should go.
Comment 5 User image :Ehsan Akhgari 2013-01-24 11:10:20 PST
Comment on attachment 702393 [details] [diff] [review]
Remove the unneeded code

[Approval Request Comment]
Bug caused by (feature/regressing bug #): bug 524944, sort of.  This was debugging code landed there and never taken out.
User impact if declined: This seems to be one of big chrome hang items that Vladan has been seeing.  As this is pretty much risk free, I think it would be nice to take it on branches.
Testing completed (on m-c, etc.): m-c
Risk to taking this patch (and alternatives if risky): this is just removing unused debugging code.  I'll say risk free.
String or UUID changes made by this patch: none.
Comment 6 User image Lukas Blakk [:lsblakk] use ?needinfo 2013-01-25 15:43:28 PST
Comment on attachment 702393 [details] [diff] [review]
Remove the unneeded code

Let's go with uplifting this to Aurora but even though it may be low risk, I think it's too late to take this on Beta and we'll just have to wait for it.

Note You need to log in before you can comment on or make changes to this bug.