1379893 - stylo: Crash in Gecko_GetStyleContext

Status: RESOLVED FIXED

(Core :: CSS Parsing and Computation, defect, P1)

Description

[Chris Peterson [:cpeterson]]

This bug was filed from the Socorro interface and is 
report bp-938fcefe-9f19-4297-944c-df6700170710.
=============================================================

9 crashes in Nightly 56.

Comment 1

[Xidorn Quan [:xidorn] UTC+11]

From the stack, I guess it crashes at https://searchfox.org/mozilla-central/rev/5dadcbe55b4ddd1e448c06c77390ff6483aa009b/layout/style/ServoBindings.cpp#346 likely that GetShell() returns nullptr, and we tries to call GetPresContext() on that nullptr.

We should probably null-check GetShell since it's prefixed Get.

Comment 2

[Kan-Ru Chen [:kanru] (UTC+9)]

I hit this while browsing https://mozilla.github.io/Fira/

bp-d12c98f0-58bc-4928-b15f-0902c0170711

Comment 3

[Xidorn Quan [:xidorn] UTC+11]

I cannot reproduce with just browsing that site.

If it is really because GetShell() returns nullptr, then it might relate more to the site you just navigate from, rather than the site you are browsing.

Comment 4

[Bobby Holley (:bholley)]

This code will go away with bug 1367904. That said, we should probably just land the null-check. I'll attach a patch.

Comment 5

[Bobby Holley (:bholley)]

Attachment: Null-check the presshell in Gecko_GetStyleContext. v1

MozReview-Commit-ID: EWTmhXnl64P

Comment 6

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/c6accdcc2c44
Null-check the presshell in Gecko_GetStyleContext. r=emilio

Comment 7

[Carsten Book [:Tomcat]]

https://hg.mozilla.org/mozilla-central/rev/c6accdcc2c44