1823429 - FetchStreamReader causes stack overflow when reading ReadableStream with a large queue

Status: RESOLVED FIXED

(Core :: DOM: Streams, defect)

Description

[Kagami Rosylight [:saschanaz] (they/them)]

new Response(new ReadableStream({ start(c) { 

for (const i of new Array(40000).fill()) {
 c.enqueue(new Uint8Array(0));
}
c.close();

} })).text();

FetchStreamReader::ChunkSteps is calling OnOutputStreamReady and that calls ReadableStreamDefaultReader::ReadChunk, which then again can call ChunkSteps synchronously. The stack becomes longer as the queue becomes larger.

Comment 1

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

Set release status flags based on info from the regressing bug 1750298

:evilpie, since you are the author of the regressor, bug 1750298, could you take a look?

For more information, please visit auto_nag documentation.

Comment 2

[Kershaw Chang [:kershaw]]

I think DOM:Streams should be the correct component.

Comment 3

[Tom S [:evilpie]]

But shouldn't the chunk length be non-zero and some point after we start reading? I am not sure why we would re-enter so often.

Comment 4

[Kagami Rosylight [:saschanaz] (they/them)]

new Uint8Array(0), that's why.

Comment 5

[Kagami Rosylight [:saschanaz] (they/them)]

Attachment: Bug 1823429 - Don't try another read from ChunkSteps r=smaug,evilpie

Comment 6

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/34e9465f50b6
Don't try another read from ChunkSteps r=smaug

Comment 7

[Web Platform Test Sync Bot [:wpt-sync] (Matrix: #interop:mozilla.org)]

Created web-platform-tests PR https://github.com/web-platform-tests/wpt/pull/39363 for changes under testing/web-platform/tests

Comment 8

[Cristina Horotan [:chorotan]]

https://hg.mozilla.org/mozilla-central/rev/34e9465f50b6

Comment 9

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

The patch landed in nightly and beta is affected.
:saschanaz, is this bug important enough to require an uplift?

• If yes, please nominate the patch for beta approval.
• If no, please set status-firefox112 to wontfix.

For more information, please visit auto_nag documentation.

Comment 10

[Kagami Rosylight [:saschanaz] (they/them)]

This is quite an edge case that I believe users won't meet in real world. I'll let it ride the train.

Comment 11

[Web Platform Test Sync Bot [:wpt-sync] (Matrix: #interop:mozilla.org)]

Upstream PR merged by moz-wptsync-bot