1717501 - Crash in [@ PLDHashTable::Search | mozilla::a11y::AccAttributes::GetAttribute]

Status: RESOLVED FIXED

(Core :: Disability Access APIs, defect)

Description

[Andrew McCreight [:mccr8]]

Maybe Fission related. (DOMFissionEnabled=1)

Crash report: https://crash-stats.mozilla.org/report/index/23c3c997-8a7a-4cc9-ba0e-eda380210615

Reason: EXC_BAD_ACCESS / KERN_INVALID_ADDRESS

Top 10 frames of crashing thread:

0 XUL PLDHashTable::Search const xpcom/ds/PLDHashTable.cpp:494
1 XUL mozilla::a11y::AccAttributes::GetAttribute accessible/base/AccAttributes.cpp:12
2 XUL mozilla::a11y::utils::GetAccAttr accessible/mac/MacUtils.mm:74
3 XUL -[mozAccessible moxRoleDescription] accessible/mac/mozAccessible.mm:534
4 XUL -[MOXAccessibleBase accessibilityAttributeValue:] accessible/mac/MOXAccessibleBase.mm:140
5 AppKit NSAccessibilityGetObjectForAttributeUsingLegacyAPI 
6 AppKit ___NSAccessibilityEntryPointValueForAttribute_block_invoke.805 
7 AppKit NSAccessibilityPerformEntryPointObject 
8 AppKit _NSAccessibilityEntryPointValueForAttribute 
9 AppKit -[NSObject _accessibilityValueForAttribute:clientError:] 

There aren't a ton of these crashes, but they are from more than one install date, and I figure there probably isn't a huge amount of people running Nightly on OSX with a11y. The stacks are a bit odd looking.

Comment 1

[Chris Peterson [:cpeterson]]

I see five crash reports from three different installations and all five crash reports have Fission enabled:

https://crash-stats.mozilla.org/signature/?signature=PLDHashTable%3A%3ASearch%20%7C%20mozilla%3A%3Aa11y%3A%3AAccAttributes%3A%3AGetAttribute&date=%3E%3D2020-12-25T19%3A05%3A00.000Z&date=%3C2021-06-25T19%3A05%3A00.000Z

Since almost 60% of Nightly users have Fission enabled, TBD whether this a11y crash is actually Fission-related.

Comment 2

[Chris Peterson [:cpeterson]]

kmag says this crash is probably not Fission related, so I will clear the Fission Milestone flag.

There have been no new crash reports after the first five reports from one user, so this crash is probably a low priority.

Comment 3

[FredMcD]

New crash: https://crash-stats.mozilla.com/report/index/bp-f7262280-9bd9-4039-b407-d841c0210826

Comment 4

[FredMcD]

https://support.mozilla.org/en-US/questions/1352124#answer-1447477

Product Firefox
Release Channel beta
Version 93.0rc1
Build ID 20210927210923 (2021-09-27)
OS OS X 10.15
OS Version 10.15.7 19H1323

bp-2a23f5fa-59cc-4553-bb51-293d20210930
bp-41db14ba-6b4e-4683-8554-d498c0210930
bp-12c51526-821f-4b4f-9ac9-e62f70210930

Comment 5

[FredMcD]

New crashes;

https://support.mozilla.org/en-US/questions/1359174

Product Firefox
Release Channel release
Version 94.0.1

bp-aa56feab-17e9-43e6-89e6-28c010211126
bp-60de3107-f370-47c2-a9d9-ea65c0211126
bp-697aa899-cb65-406f-a55e-d60b20211126 = Uptime 254 seconds (4 minutes and 14 seconds)

Signature: PLDHashTable::Search | mozilla::a11y::AccAttributes::GetAttribute
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Product Firefox
Release Channel release
Version 94.0.2

bp-2e7d11aa-c0bd-4fc7-8953-c2fa00211126
bp-89f92912-805f-4f22-9fdb-f38f90211126
bp-7bd0015d-4e9c-4ed6-b528-289c00211126

Signature: PLDHashTable::Search | mozilla::a11y::AccAttributes::GetAttribute

Comment 6

[Ryan VanderMeulen [:RyanVM]]

Hi Jamie, this is one of the more frequent a11y crashes we're currently seeing in the wild. Can you help find someone to investigate? Thanks!

Comment 7

[James Teh [:Jamie]]

I guess Accessible::Attributes returns null for some reason, perhaps a dead RemoteAccessible? Eitan, would you mind looking into this?

Comment 8

[Eitan Isaacson [:eeejay]]

Attachment: Bug 1717501 - Null check attributes in MacUtils::GetAccAttr. r?morgan

Comment 9

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/01ad3820abe4
Null check attributes in MacUtils::GetAccAttr. r=morgan

Comment 10

[Noemi Erli[:noemi_erli]]

https://hg.mozilla.org/mozilla-central/rev/01ad3820abe4

Comment 11

[BugBot [:suhaib / :marco/ :calixte]]

The patch landed in nightly and beta is affected.
:eeejay, is this bug important enough to require an uplift?
If not please set status_beta to wontfix.

For more information, please visit auto_nag documentation.

Comment 12

[Eitan Isaacson [:eeejay]]

Comment on attachment 9263363 [details]
Bug 1717501 - Null check attributes in MacUtils::GetAccAttr. r?morgan

Beta/Release Uplift Approval Request

• User impact if declined: Periodic crashes
• Is this code covered by automated tests?: No
• Has the fix been verified in Nightly?: Yes
• Needs manual test from QE?: No
• If yes, steps to reproduce:
• List of other uplifts needed: None
• Risk to taking this patch: Low
• Why is the change risky/not risky? (and alternatives if risky): This is a simple null check.
• String changes made/needed:

Comment 13

[Pascal Chevrel:pascalc (PTO until April 26)]

Comment on attachment 9263363 [details]
Bug 1717501 - Null check attributes in MacUtils::GetAccAttr. r?morgan

Approved for 98 beta 5, thanks.

Comment 14

[Pascal Chevrel:pascalc (PTO until April 26)]

https://hg.mozilla.org/releases/mozilla-beta/rev/37f1c2ae7505

Comment 15

[Ryan VanderMeulen [:RyanVM]]

Comment on attachment 9263363 [details]
Bug 1717501 - Null check attributes in MacUtils::GetAccAttr. r?morgan

Simple null check for a pretty common crash, let's get this on ESR also. Approved for 91.7esr.

Comment 16

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/releases/mozilla-esr91/rev/8c08140677e7