375619 - "franken" firefox on disk if you kill updater.exe mid-way, should we attempt to restore moz-backup files if update.status == "applying"?

Status: RESOLVED WONTFIX

(Toolkit :: Application Update, defect)

Description

[(not reading, please use [e-mail] instead)]

"franken" firefox on disk if you kill updater.exe mid-way

justin and I saw this with bug #373908

steps to reproduce:

1)  run firefox, get an update
2)  restart, while update is applying (updater is running), kill it.  This is easy when you hit bug bug #373908 as it hits an infinite loop and pings the CPU.

when you start firefox back up, you'll be in a "fraken" firefox state, and weirdness can ensue because some of your files are "old" and some are "new"

your update.status file will have "applying", and your firefox app dir will have .moz-backup files.

one thing we could do is detect this "applying" state and restore all the .moz-backup files

Comment 1

[(not reading, please use [e-mail] instead)]

note, if I had a franken-fox and I received a complete update, that should fix the problem (as a complete update would reset things).  That is assuming we could handle .moz-backup files that already exists (not sure about that, I need to check.)

I think we should consider fixing this bug for Firefox 3 so that we are more robust about handling a sudden death of updater.exe

Comment 2

[(not reading, please use [e-mail] instead)]

benjamin, would this scenario still be a problem after your proposed improvements to updater?

Comment 3

[Benjamin Smedberg]

Yes, but it's much less likely since we're not doing any I/O and updater is almost instantaneous.

However, it can leave behind .moz-backup files in the somewhat-ordinary case that there are DLLs in use when the update happens (e.g. AccessibleMarshal.dll).

Comment 4

[Robert Helmer [:rhelmer]]

Also note that backup_restore uses copy (see the comment :P):

http://mxr.mozilla.org/mozilla-central/source/toolkit/mozapps/update/src/updater/updater.cpp#488

If the "sudden death" happens when restoring from backup then you probably end up with corrupt files.

(In reply to comment #1)
> note, if I had a franken-fox and I received a complete update, that should fix
> the problem (as a complete update would reset things).  That is assuming we
> could handle .moz-backup files that already exists (not sure about that, I need
> to check.)

Since the initial backup_create is a copy, how do we know that the updater wasn't killed while making the backup? It seems like we want to try to apply a complete in this scenario, I'm not sure that restoring the moz-backup file is safe..

Comment 6

[Robert Strong (they/them - no direct email)]

The number of frankenfoxes appear to be extremely small now and I think it is better to spend time and effort lessening that number further instead of fixing bugs like this which are extreme edgecases.

Total crashes processed : 31761889

Firefox 3.5 Mismatched File Version Report
20101204 through 20110411

Summary
=============================
    Lines processed : 1711982
  Crashes processed : 1721575
      Lines skipped :     361
   Total mismatches :  137788
 Percent mismatches :   8.00%

Skipped Line Breakdown
===============================
 Invalid firefox.exe name : 309
     Missing version info :  52

Mismatched Versions
==============================================================================+
                        |      Total       | DLLVer < FFVer  | DLLVer > FFVer |
                        +------------------+-----------------+----------------+
       Total mismatches : 137788 (100.00%) | 135850 (98.59%) |  1938 (1.41%)  |
 browserdirprovider.dll :  13507   (9.80%) |  11575  (8.40%) |  1932 (1.40%)  |
           brwsrcmp.dll :   6087   (4.42%) |   4894  (3.55%) |  1193 (0.87%)  |
              xpcom.dll : 101843  (73.91%) | 101810 (73.89%) |    33 (0.02%)  |
                xul.dll : 135854  (98.60%) | 135823 (98.57%) |    31 (0.02%)  |
                        +------------------+-----------------+----------------+


Firefox 3.6 Mismatched File Version Report
20101204 through 20110411

Summary
==============================
    Lines processed : 20277061
  Crashes processed : 20278718
      Lines skipped :     3797
   Total mismatches :    49995
 Percent mismatches :    0.25%

Skipped Line Breakdown
================================
      Invalid line format :   34
 Invalid firefox.exe name : 2907
     Missing version info :  857

Mismatched Versions
==============================================================================+
                        |      Total       | DLLVer < FFVer  | DLLVer > FFVer |
                        +------------------+-----------------+----------------+
       Total mismatches :  49995 (100.00%) |   1039 (2.08%)  | 48956 (97.92%) |
 browserdirprovider.dll :  48685  (97.38%) |    370 (0.74%)  | 48315 (96.64%) |
           brwsrcmp.dll :  48465  (96.94%) |    351 (0.70%)  | 48114 (96.24%) |
              xpcom.dll :  16297  (32.60%) |    426 (0.85%)  | 15871 (31.75%) |
                xul.dll :   7903  (15.81%) |    877 (1.75%)  |  7026 (14.05%) |
                        +------------------+-----------------+----------------+


Firefox 4.0 Mismatched File Version Report
20101111 through 20110411

Summary
=============================
    Lines processed : 9750994
  Crashes processed : 9761596
      Lines skipped :     954
   Total mismatches :    3679
 Percent mismatches :   0.04%

Skipped Line Breakdown
===============================
      Invalid line format :  46
 Invalid firefox.exe name : 246
     Missing version info : 664

Mismatched Versions
==============================================================================+
                        |      Total       | DLLVer < FFVer  | DLLVer > FFVer |
                        +------------------+-----------------+----------------+
       Total mismatches :  3679 (100.00%)  |    95 (2.58%)   |  3584 (97.42%) |
       browsercomps.dll :  3501  (95.16%)  |    82 (2.23%)   |  3419 (92.93%) |
           mozalloc.dll :  2110  (57.35%)  |    77 (2.09%)   |  2033 (55.26%) |
              xpcom.dll :  2067  (56.18%)  |    75 (2.04%)   |  1992 (54.15%) |
                xul.dll :  2531  (68.80%)  |    77 (2.09%)   |  2454 (66.70%) |
                        +------------------+-----------------+----------------+

[reply] [-]
Private
Comment 26 Robert Strong [:rstrong] (do not email) 2011-04-13 22:50:16 PDT

Going back just two weeks of Firefox 4 the numbers are tad better coming in at
0.02% vs 0.05% and the same is true going back 4 weeks.

Firefox 4.0 Mismatched File Version Report
20110329 through 20110411

Summary
============================
    Lines processed : 841619
  Crashes processed : 841894
      Lines skipped :     84
   Total mismatches :    175
 Percent mismatches :  0.02%

Skipped Line Breakdown
==============================
      Invalid line format :  1
 Invalid firefox.exe name : 16
     Missing version info : 67

Mismatched Versions
==============================================================================+
                        |      Total       | DLLVer < FFVer  | DLLVer > FFVer |
                        +------------------+-----------------+----------------+
       Total mismatches :   175 (100.00%)  |    5 (2.86%)    |  170 (97.14%)  |
       browsercomps.dll :   169  (96.57%)  |    4 (2.29%)    |  165 (94.29%)  |
           mozalloc.dll :    94  (53.71%)  |    4 (2.29%)    |   90 (51.43%)  |
              xpcom.dll :    98  (56.00%)  |    4 (2.29%)    |   94 (53.71%)  |
                xul.dll :   147  (84.00%)  |    5 (2.86%)    |  142 (81.14%)  |
                        +------------------+-----------------+----------------+