482236 - negative trace-refcnt "total" confuses runtests.py.in: "missing output line for total leaks!"

Status: VERIFIED FIXED

(Testing :: Mochitest, defect)

Description

[Serge Gautherie (:sgautherie)]

{
http://tinderbox.mozilla.org/showlog.cgi?log=Firefox3.1/1236595575.1236601337.20655.gz
OS X 10.5.2 mozilla-1.9.1 unit test on 2009/03/09 03:46:15

== BloatView: ALL (cumulative) LEAK AND BLOAT STATISTICS

     |<----------------Class--------------->|<-----Bytes------>|<----------------Objects---------------->|<--------------References-------------->|
                                              Per-Inst   Leaked    Total      Rem      Mean       StdDev     Total      Rem      Mean       StdDev
   0 TOTAL                                          -6        0 -1246128631        0 (197615.31 +/-     0.00) 1540625252        0 (13864.30 +/-     0.00)
 807 nsRect                                         16        0 -1910456423        0 (717255.44 +/-     0.00)        0        0 (    0.00 +/-     0.00)

nsTraceRefcntImpl::DumpStatistics: 1161 entries
TEST-UNEXPECTED-FAIL | runtests-leaks | missing output line for total leaks!
}

Obviously the 'TOTAL' line is there:
the regexp must be too restrictive.

Comment 1

[Serge Gautherie (:sgautherie)]

Ftr, the box turned Orange but didn't report this failure:
this is expected fttb, see bug 473259 (Av1 patch...).

This code will move in bug 469518 (Bv1a patch),
so wait for that before check-in.

Comment 2

[Serge Gautherie (:sgautherie)]

Attachment: (Av1) Support a negative 'Total' value [Checkin: See comment 12 & 15]

Comment 3

[David Baron :dbaron: (⌚️UTC-4, no longer working on Mozilla)]

Comment on attachment 366303 [details] [diff] [review]
(Av1) Support a negative 'Total' value
[Checkin: See comment 12 & 15]

r=dbaron

However, I don't own this file, so Waldo should review as well.

Comment 4

[Serge Gautherie (:sgautherie)]

Very similar case:
{
http://tinderbox.mozilla.org/showlog.cgi?log=Firefox/1236909599.1236917444.7220.gz
OS X 10.5.2 mozilla-central unit test on 2009/03/12 18:59:59
}

Comment 5

[Serge Gautherie (:sgautherie)]

Ftr, this column is
{
http://mxr.mozilla.org/mozilla-central/source/xpcom/base/nsTraceRefcntImpl.cpp

206     mTotalLeaked = 0;

305     total->mTotalLeaked += (PRInt32)(mClassSize *
306                                      ((mNewStats.mCreates + mAllStats.mCreates)
307                                       -(mNewStats.mDestroys + mAllStats.mDestroys)));

367               (nsCRT::strcmp(mClassName, "TOTAL"))
368                   ?(PRInt32)((stats->mCreates - stats->mDestroys) * mClassSize)
369                   :mTotalLeaked,

384   PRInt32       mTotalLeaked; // used only for TOTAL entry
}

Comment 6

[Mike Connor [:mconnor]]

How do we have more destroys than creates?  How can we have a negative number on a leak test?

Comment 7

[David Baron :dbaron: (⌚️UTC-4, no longer working on Mozilla)]

In the case in comment 0, I have no idea.

More typically it happens either:
 * because of a bug in instrumentation (e.g., instrumenting some but not all constructors, often because of an implicit copy-constructor)
 * because we actually called an object's destructor twice

But to figure out what happened in comment 0 somebody would need to debug.

Comment 8

[Jesse Ruderman]

http://tinderbox.mozilla.org/showlog.cgi?log=Firefox/1237094971.1237104878.374.gz#err0

The total number of nsRect objects is reported as negative, but 0 are reported remaining.  Could it be that mochitests create enough nsRect objects to overflow the counter?

Comment 9

[Jesse Ruderman]

Filed bug 483500 based on that theory.

Comment 10

[Serge Gautherie (:sgautherie)]

(In reply to comment #8)
> http://tinderbox.mozilla.org/showlog.cgi?log=Firefox/1237094971.1237104878.374.gz#err0

OS X 10.5.2 mozilla-central unit test on 2009/03/14 22:29:31

Comment 11

[Daniel Holbert [:dholbert]]

http://tinderbox.mozilla.org/showlog.cgi?log=Firefox3.1/1237237673.1237244013.345.gz
OS X 10.5.2 mozilla-1.9.1 unit test on 2009/03/16 14:07:53

Comment 12

[Serge Gautherie (:sgautherie)]

Comment on attachment 366303 [details] [diff] [review]
(Av1) Support a negative 'Total' value
[Checkin: See comment 12 & 15]


http://hg.mozilla.org/mozilla-central/rev/95497d18ce82
Av1, with comment 1 suggestion(s),
plus removing a no longer needed |abs()| which I had missed.

Comment 13

[Serge Gautherie (:sgautherie)]

V.Fixed, per bug 483917 comment 0.

Comment 14

[Serge Gautherie (:sgautherie)]

http://tinderbox.mozilla.org/showlog.cgi?log=Firefox3.5/1237891787.1237897818.12685.gz
OS X 10.5.2 mozilla-1.9.1 unit test on 2009/03/24 03:49:47

Comment 15

[Serge Gautherie (:sgautherie)]

Comment on attachment 366303 [details] [diff] [review]
(Av1) Support a negative 'Total' value
[Checkin: See comment 12 & 15]


http://hg.mozilla.org/releases/mozilla-1.9.1/rev/abe9562544ef