1331286 - Crash in mozilla::a11y::DocAccessibleWrap::GetNativeWindow

Status: RESOLVED FIXED

(Core :: Disability Access APIs, defect)

Description

[Nicholas Nethercote [inactive]]

This bug was filed from the Socorro interface and is 
report bp-ca7b3fd1-4a7a-41d9-b247-ab2242170114.
=============================================================

This first happened twice in Nightly 20161221030226, then once in 20170110075905, then it spiked in 20170113030227 (making it the #10 topcrash) and has been happening more frequently since then.

The regression window for 20170113030227 is here:

https://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=97d6f73643940256c0eb61e384c49bf6f6c49847&tochange=91f5293e9a89056565493ed5073c3842b0ee9fdc

The crash address is usually 0x10, though sometimes 0xc or 0x. So it looks like |ipcDoc| might be null, though in some of them perhaps it's |tab| that is null.

tbsaunde, any ideas?

Comment 1

[Trevor Saunders (:tbsaunde)]

So, getting to this point is kind of odd, normally in a content process IPCAccessibilityActive() would return true, and HandleAccEvent() would have returned before getting to this point.  The one obvious way for this to happen is for someone to set the accessibility.ipc_architecture_enabled pref to false, that would make IPCAccessibilityActive() return false in content processes, and then its probably possible at some point while a document is being shut down for IPCDoc() to return null.  I don't think we gain anything from that pref so I'll remove and and hopefully this will be fixed.

Comment 2

[Trevor Saunders (:tbsaunde)]

Attachment: remove accessibility.ipc_architecture_enabled pref

Comment 3

[David Bolter [:davidb] (NeedInfo me for attention)]

Comment on attachment 8827104 [details] [diff] [review]
remove accessibility.ipc_architecture_enabled pref

Review of attachment 8827104 [details] [diff] [review]:
-----------------------------------------------------------------

Probably ok but I'd like jimm's feedback.

Comment 4

[David Bolter [:davidb] (NeedInfo me for attention)]

> Probably ok but I'd like jimm's feedback.

(Because he handles most (all?) the prefs around e10s shipping)

Comment 5

[Jim Mathies [:jimm]]

Comment on attachment 8827104 [details] [diff] [review]
remove accessibility.ipc_architecture_enabled pref

Review of attachment 8827104 [details] [diff] [review]:
-----------------------------------------------------------------

seems fine, we've never used this and I can't find any references to it.

Comment 6

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/mozilla-inbound/rev/fb95edfbf857
remove accessibility.ipc_architecture_enabled pref r=davidb

Comment 7

[Phil Ringnalda (:philor)]

https://hg.mozilla.org/mozilla-central/rev/fb95edfbf857