411752 - Leak nsDownloadManager and more after downloading file

Status: NEW

(Toolkit :: Downloads API, defect)

Description

[Carsten Book [:Tomcat]]

Attachment: leag log

Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.4; en-US; rv:1.9b3pre) Gecko/2008011009 Firefox/3.0b3pre

Steps to reproduce: 
-> new Firefox Profile
-> download a file (in my case it was a 59 MB big file)
-> wait till the download is finished
-> Close Firefox with the download manager window open


nsStringStats
 => mAllocCount:          24058
 => mReallocCount:         3306
 => mFreeCount:           24056  --  LEAKED 2 !!!
 => mShareCount:          19468
 => mAdoptCount:           2214
 => mAdoptFreeCount:       2214

Comment 1

[Jonas Sicking (:sicking) No longer reading bugmail consistently]

This looks like a bug in the download manager. One that looks bad to me given that downloading stuff is decently common.

Comment 2

[Jesse Ruderman]

I don't think I'm seeing this bug.  Can you be more specific in your steps to reproduce, e.g. saying what action you took to start the download and to close Firefox?

Comment 3

[Carsten Book [:Tomcat]]

(In reply to comment #2)
> I don't think I'm seeing this bug.  Can you be more specific in your steps to
> reproduce, e.g. saying what action you took to start the download and to close
> Firefox?
> 

Hi Jesse, yes sure:

My Download Manager Histroy contained before one entry before (also one mp3 File). Then i have downloaded http://www.newmixes.com/download/patrice_strike-club_fg_radio_fg-sat-01-07-2008-newmixes.mp3 (the idea yesterday was to test something for Bug 410680).

Download Manager is set to default setting = Show Download Manager ... and save all files to Desktop.

When i clicked on this download link above i got the "What Firefox should do with this File Dialog" and click on "Save File"

With Download Manager open i waited till the Download is complete and shutdown Firefox. I noticed also that the Download Notification bar was also visible when i closed Firefox, so maybe this could be one factor here.

In short my steps to reproduce today where:
Go to www.newmixes.com
Download one or more files
When the Download is complete and you see the Download Notification Bar
Close Firefox
Leak

Comment 4

[Carsten Book [:Tomcat]]

Attachment: leak log2

Leak Log from the testing today and the steps to reproduce from comment #3

nsTraceRefcntImpl::DumpStatistics: 769 entries
nsStringStats
 => mAllocCount:          32807
 => mReallocCount:         3994
 => mFreeCount:           32805  --  LEAKED 2 !!!
 => mShareCount:          30349
 => mAdoptCount:           3524
 => mAdoptFreeCount:       3524

Comment 5

[Carsten Book [:Tomcat]]

Attachment: complete debug output

maybe this helps

Comment 6

[Shawn Wilsher :sdwilsh]

(In reply to comment #3)
> With Download Manager open i waited till the Download is complete and shutdown
> Firefox. I noticed also that the Download Notification bar was also visible
> when i closed Firefox, so maybe this could be one factor here.
What is the Download Notification bar that you are referring to here?

Comment 7

[Carsten Book [:Tomcat]]

(In reply to comment #6)
> What is the Download Notification bar that you are referring to here?
> 

The small popup that comes up every times a download is finished. 

Comment 8

[Carsten Book [:Tomcat]]

Attachment: new leak log

new leak log from  Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.4; en-US; rv:1.9b3pre) Gecko/2008012105 Firefox/3.0b3pre

Comment 9

[Shawn Wilsher :sdwilsh]

Well, this leak makes sense if the nsIAlertsService box was still showing.  Does it leak when that goes away?  nsAlertsService holds onto a reference of the observer, which for the download complete notification, is nsDownloadManager:
http://bonsai.mozilla.org/cvsblame.cgi?file=/mozilla/toolkit/components/alerts/src/nsAlertsService.cpp&rev=1.7#141
http://bonsai.mozilla.org/cvsblame.cgi?file=/mozilla/toolkit/components/downloads/src/nsDownloadManager.cpp&rev=1.155#1834

Comment 10

[Carsten Book [:Tomcat]]

(In reply to comment #9)
> Well, this leak makes sense if the nsIAlertsService box was still showing. 
> Does it leak when that goes away?  nsAlertsService holds onto a reference of
> the observer, which for the download complete notification, is
> nsDownloadManager:
> http://bonsai.mozilla.org/cvsblame.cgi?file=/mozilla/toolkit/components/alerts/src/nsAlertsService.cpp&rev=1.7#141
> http://bonsai.mozilla.org/cvsblame.cgi?file=/mozilla/toolkit/components/downloads/src/nsDownloadManager.cpp&rev=1.155#1834
> 

Yeah confirmed. You see the leak when you close Firefox with the download complete notification open, without its not leaking

Comment 11

[Shawn Wilsher :sdwilsh]

So, is this invalid then?  It only leaks when nsIAlertsService is "working"

Comment 12

[Jesse Ruderman]

"Shutdown leaks" are still bugs that should be fixed, if only to make leak testing easier.

Comment 13

[Shawn Wilsher :sdwilsh]

It's more like a race condition leak in this case - it's only if the nsAlertsService box is still visible.

Comment 14

[Jonas Sicking (:sicking) No longer reading bugmail consistently]

It does make it a whole lot harder to find other leaks though. Especially since it's much harder to find regressions from N objects than from 0 since we have to keep track of what operations have "ok" leaks for what objects.

But I agree it's much lower priority to fix a leak like this than something that builds up over time.

But if you do have any info on what is going wrong here please do post it.

Comment 15

[Jonas Sicking (:sicking) No longer reading bugmail consistently]

Not blocking on this since it won't affect end users. I.e. the "leak" is only there if you shut down at the wrong time. It won't accumulate over time.