Crash in nsOfflineCacheDevice::Evict

RESOLVED FIXED in Firefox 50

Status

()

Core
Networking: Cache
--
critical
RESOLVED FIXED
2 years ago
2 years ago

People

(Reporter: jchen, Assigned: mayhemer)

Tracking

({crash})

unspecified
mozilla51
Unspecified
Windows 8
crash
Points:
---

Firefox Tracking Flags

(firefox50 fixed, firefox51 fixed)

Details

(Whiteboard: [necko-active], crash signature)

Attachments

(1 attachment)

(Reporter)

Description

2 years ago
This bug was filed from the Socorro interface and is 
report bp-abd25789-9746-49cb-856e-23dd22160713.
=============================================================

Low level crash that seems to have started with the 20160711034039 Nightly. So far, there is 1 crash from 20160711 nightly and 5 crashes from 20160712 nightly (0.38% of crashes for that nightly).
Assignee: nobody → honzab.moz
Whiteboard: [necko-active]
Status: NEW → ASSIGNED
Created attachment 8775276 [details] [diff] [review]
v1 (nullchecks added everywhere)

These should be all places where we may access either mDB or the db statements.  The statements and mDB are nullified during shutdown.  The added checks should be safe, because w/o them we would crash anyway (null deref).  However, I'm not sure what this can all break, since the appcache shutdown/lifetime is fragile (bug 1289871)

https://treeherder.mozilla.org/#/jobs?repo=try&revision=973681dfd541
Attachment #8775276 - Flags: review?(michal.novotny)
Crash volume for signature 'nsOfflineCacheDevice::Evict':
 - nightly (version 50): 94 crashes from 2016-06-06.
 - aurora  (version 49): 0 crash from 2016-06-07.
 - beta    (version 48): 0 crash from 2016-06-06.
 - release (version 47): 0 crash from 2016-05-31.
 - esr     (version 45): 0 crash from 2016-04-07.

Crash volume on the last weeks:
             Week N-1   Week N-2   Week N-3   Week N-4   Week N-5   Week N-6   Week N-7
 - nightly         44         26          0          0          0          0          0
 - aurora           0          0          0          0          0          0          0
 - beta             0          0          0          0          0          0          0
 - release          0          0          0          0          0          0          0
 - esr              0          0          0          0          0          0          0

Affected platforms: Windows, Mac OS X, Linux
status-firefox50: --- → affected
Attachment #8775276 - Flags: review?(michal.novotny) → review+
Keywords: checkin-needed

Comment 3

2 years ago
Pushed by cbook@mozilla.com:
https://hg.mozilla.org/integration/mozilla-inbound/rev/b1d546948211
Add after-shutdown nullchecks to the appcache code, r=michal
Keywords: checkin-needed

Comment 4

2 years ago
bugherder
https://hg.mozilla.org/mozilla-central/rev/b1d546948211
Status: ASSIGNED → RESOLVED
Last Resolved: 2 years ago
status-firefox51: --- → fixed
Resolution: --- → FIXED
Target Milestone: --- → mozilla51

Comment 5

2 years ago
Hi Honza, this is a top crasher on Aurora50. Should we consider uplifting the patch to Aurora? Thanks!
Flags: needinfo?(honzab.moz)
Comment on attachment 8775276 [details] [diff] [review]
v1 (nullchecks added everywhere)

Approval Request Comment
[Feature/regressing bug #]: not a regression
[User impact if declined]: shutdown nul-deref crash
[Describe test coverage new/current, TreeHerder]: landed on m-c recently, we have tests that exercise this code
[Risks and why]: zero, this is not a widely used and critical feature and it's nothing more than an added null-check, all where it correctly belongs
[String/UUID change made/needed]: none
Flags: needinfo?(honzab.moz)
Attachment #8775276 - Flags: approval-mozilla-aurora?

Comment 7

2 years ago
Comment on attachment 8775276 [details] [diff] [review]
v1 (nullchecks added everywhere)

The patch is pretty big but it seems to have eliminated the associated crash signature from Nightly, let's uplift to Aurora50+
Attachment #8775276 - Flags: approval-mozilla-aurora? → approval-mozilla-aurora+

Comment 8

2 years ago
bugherderuplift
https://hg.mozilla.org/releases/mozilla-aurora/rev/6307dc2381b5
status-firefox50: affected → fixed
This is still reproducible on Fx50 in relatively low volume, based on crash data from the last ~2 months.

  SIGNATURE   | nsOfflineCacheDevice::Evict
  -----------------------------------------
  CRASH STATS | http://tinyurl.com/zb58on2
  -----------------------------------------
  OVERVIEW    | 0 crashes on nightly 52
	      | 4 crashes on nightly 51
	      | 0 crashes on aurora 51
	      | 10 crashes on nightly 50
	      | 109 crashes on aurora 50
	      | 2 crashes on beta 50
(In reply to Andrei Vaida, QA [:avaida] – please ni? me from comment #9)
> This is still reproducible on Fx50 in relatively low volume, based on crash
> data from the last ~2 months.
> 
>   SIGNATURE   | nsOfflineCacheDevice::Evict
>   -----------------------------------------
>   CRASH STATS | http://tinyurl.com/zb58on2
>   -----------------------------------------
>   OVERVIEW    | 0 crashes on nightly 52
> 	      | 4 crashes on nightly 51
> 	      | 0 crashes on aurora 51
> 	      | 10 crashes on nightly 50
> 	      | 109 crashes on aurora 50
> 	      | 2 crashes on beta 50

I checked few of the reports and all of the crashes are revisions without the fix.  This bug is actually fixed then.
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