66730 - Hang on exit after opening many windows

Status: VERIFIED INVALID

(SeaMonkey :: UI Design, defect, P1)

Description

[Dimitrios]

Huge memory leak when opening quite a few browser windows. E.g. go to Bugzilla
Bug Query page and retrieve a page with a modest number of links (bugs). Say,
100 of them.
A file like this is smaller than 200Kb. From that page, open at least 30 links
using "Open link in New Window". Free ram memory (as reported by System Monitor)
gradually falls 40MB (there were 133 MB left before opening Mozilla). From that
point, links opened in new windows are always blank. When trying to close them,
you get something like that shown in the gif attachment. A Personal Security
Manager window is also showing, although I never use this feature. After
shutting down all windows, mozilla is still in memory and shutting down Mozilla
remnant (using taskmanager) is needed in order to be able to use Mozilla again.

Comment 1

[Dimitrios]

Attachment: screenshot after Mozilla crash (System Monitor is also shown)

Comment 2

[Brian Haskin (Janzert)]

I can confirm this, although it acts slightly different for me. 
After opening enough windows to consume all of the physical memory the last
window opened will look like the screen shot the original reporter submitted.
Attempting to open any more windows doesn't do anything. I can then close all
the instances of mozilla which frees up ~14MB's. After closing all the windows
there is still an instance of mozilla left in the task manager that has to be
killed. Once the remaining instance is killed another 56MB's are freed and
mozilla can be restarted without a problem.

user agent: Mozilla/5.0 (Windows; U; Win98; en-US; m18) Gecko/20010208
build: 2001020804

Comment 3

[Brian Haskin (Janzert)]

Just want to clarify that the real bug here seems to be a hang on exit after a
low memory condition, not necessarily a memory leak.

Changing component to XP Apps from Networking: Cache
Changing Summary from "Memory leak and crash after opening many windows"

Comment 4

[Blake Ross]

Alec, wanna look into this?  If not, send to me.

Comment 5

[Alec Flett]

you got it.

Comment 6

[Blake Ross]

Is this still a major problem, or is this just a general "Mozilla uses too much 
memory"?

Comment 7

[Dimitrios]

I tested with a 2001041704 build and the problem remains although slightly
different: No PSM window this time. The "turning point is still the same, i.e.
more than 30-35 windows (but I admit the test case is poor). A warning message
box is displayed: "There is not enough memory to create or display graphic".
Start menu doesn't work.
I don't think it is a simple raw memory consumption problem. When it happens,
System Monitor was showing 65 MB swapfile but the 52 MB Disk cache indication
might suggest that there was plenty of system memory. There is something that
prevents OS from sharing memory resources effectively.
Tested on Win98, 192 MB ram.

Comment 8

[Brian Kaul]

Possibly related to bug 78582 ?  I posted as a separate bug due to differences
in behavior of hang - I don't see excessive memory usage, and no PSM window, but
I do get a hang on exit after maybe 6-10 windows have been used... 

Build 2001050104 Win2k

Comment 9

[Blake Ross]

I can't really reproduce this...I need specific steps.

Comment 10

[Dimitrios]

Things were changed from the time of my initial report. The problem now doesn't
seem to be relevant to Mozilla itself. It's rather a Win98 bug.
I tried the following test case on a Win98 system with 192 MB ram. Applications
tested were Mozilla (2001061520 build), Communicator 4.73 and IE 5.5. The
results were quite amusing: both NS4.73 and IE 5.5 cause themselves and Start
Menu malfunctioning exhibit even at 90 mb free ram (about 20-30 windows open)
while Mozilla does no harm until approaching the point where free ram is
exhausted (44 windows)! 

BTW, I also tested on Win2k and found this OS is totally bulletproof, regarding
to this issue. Can anyone apply the test case on Opera and Win98 and report us
the result ? Anyway, please test both IE 5.5 and Mozilla before closing this
bug, in order to confirm my tests.

TEST CASE:
1. Open http://www.mozilla.org/quality/help/bug-form.html and save it on your
local disk. This will be the test case html.
2. Set "Last Page Visited" in Preferences->Navigator.
3. Close all other apps, except a memory monitor utility like SpyGuru or,
preferably, MS-SysMon and the browser. Open saved page, then subsequently open
new browser windows (Ctrl+N) until free ram is about 6-10 MB. I had to open 44
windows before reproducing it (7.5  MB free of 192 MB ram, no swap file usage
reported by SysMon).
4. At this point, try to open pull down menus in Mozilla and Windows Start Menu.
Menus appear blank. Additionally, closing windows from the Windows Taskbar is
extremely slow (only for Mozilla). If you can't still reproduce the issue, open
just a few more windows. For Mozilla, the problem always appear when approaching
(not neccesarily reaching) the threshold where there's no ram left and the
system is going to use the swap file. Situation is recoverable, i.e. after
closing a few windows the system becomes usable again. The latter is one of the
big differences to the original report (another one is that no PSM garbage is
observed).

Comment 11

[Jay Huron]

I have had this problem using Win98SE and Moz build 9.2. If there are numourous
windodws opened and closed. (maybe just open at once) Mozilla will stay resident
in the Windows Task Manager after all windows are closed untill you "end task".
If Moz. is still being used when this happnes, links will stop reponding and if
opened with the "open in new browser window", the new page will be blank.

Comment 12

[Dimitrios]

Jay, could you test IE 5.5 on the same machine ? If you also see the same kind
of problems after opening quite a few windows on IE, then I must close this bug
(it would be an OS memory management bug).

Comment 13

[Jay Huron]

I opened about 20-22 windows in IE5 and it gave me a system dangerously low on 
resorces message and asked if I wanted to shut down IE. (some of the windows 
didn't display all the buttons at the top also) I shut down IE and now it shows 
up in the task manager when there are no IE windows open. However, it didn't 
have the problem of not being able to click any links if I open a browser 
window or opening blank pages when I open a link in a new window. IE does not 
seem to have any ill affects in this state.

Comment 14

[Blake Ross]

I have seen the problem Jay mentions, about Mozilla not really closing. But that
cropped up more recently, it certainly hasn't been around since January.  I
don't think there is a real bug here anymore that has been around since January
except that window closing is slow and Mozilla uses a lot of memory. We know that.

Comment 15

[Dimitrios]

Verified.