Bug 201871

Summary:

AbortSignal does not always emit the abort signal

Product:

WebKit

Reporter:

Jesse van den Kieboom <jkieboom>

Component:

DOM

Assignee:

youenn fablet <youennf>

Status:

RESOLVED FIXED

Severity:

Normal

CC:

ap, cdumez, commit-queue, dbates, dpaddock, esprehn+autocc, ews-watchlist, kangil.han, kondapallykalyan, sam, webkit-bug-importer, youennf

Priority:

Keywords:

InRadar

Version:

Safari 12

Hardware:

Mac

OS:

macOS 10.14

Attachments:

Description	Flags
Abort signal appears evicted under GC pressure	none
Patch	none

Jesse van den Kieboom

Reported 2019-09-17 06:32:03 PDT

This problem occurs in a large code base and I am having trouble setting up a simple reproducible test case outside of our application. It looks like when using an AbortController, calling abort on it may in certain circumstances not emit the abort event on the corresponding signal. It feels like this is problem of premature garbage collection because if I plug the corresponding signal on another object that is kept alive, I do receive the abort event correctly. In addition, the problem in our application does not appear if I use an AbortController/AbortSignal shim (further indicating that this is a problem in the native implementation somehow). I'll try to come up with an isolated test case, but I'm having a hard time doing so.

Attachments
Abort signal appears evicted under GC pressure (649 bytes, text/javascript) 2019-09-17 06:42 PDT, Jesse van den Kieboom	no flags	Details
Patch (14.70 KB, patch) 2019-10-04 07:26 PDT, youenn fablet	no flags	Details Formatted Diff Diff
View All Add attachment proposed patch, testcase, etc.

Jesse van den Kieboom

Comment 1 2019-09-17 06:42:26 PDT

Created attachment 378960 [details] Abort signal appears evicted under GC pressure I'm not confident this is the smallest repro case, and it doesn't appear to _always_ reproduce the problem. For me this seems to trigger the issue one out of three times or so.

Alexey Proskuryakov

Comment 2 2019-09-17 13:09:16 PDT

This seems like it's most likely an issue in AbortController, which is not part of WebKit. I think that your hunch is correct, and this is related to garbage collection. So perhaps AbortController needs to protect its properties from collection. Please feel free to re-open if you find evidence of this being a WebKit bug. We'll almost certainly need a reproducible test case to work on this.

Dasa Paddock

Comment 3 2019-09-17 13:30:10 PDT

Can this be reopened with the Component set to WebCore since the code is at: https://trac.webkit.org/browser/webkit/trunk/Source/WebCore/dom/AbortController.cpp

Alexey Proskuryakov

Comment 4 2019-09-17 13:37:25 PDT

Apologies, turns out that I didn't know what I was taking about.

Radar WebKit Bug Importer

Comment 5 2019-09-17 13:37:42 PDT

<rdar://problem/55451712>

youenn fablet

Comment 6 2019-10-04 07:26:11 PDT

Created attachment 380219 [details] Patch