2036145 - Assertion failure: NS_IsMainThread() (Wrong thread!), at /builds/worker/checkouts/gecko/xpcom/threads/nsThreadManager.cpp:248

Status: RESOLVED FIXED

(Core :: DOM: Web Serial, defect)

Description

[Tyson Smith [:tsmith]]

Attachment: testcase.html

Found while fuzzing m-c 20260413-1f396df9f27e (--enable-debug --enable-fuzzing)

To reproduce via Grizzly Replay:

$ pip install fuzzfetch grizzly-framework --upgrade
$ python -m fuzzfetch -d --fuzzing -n firefox
$ python -m grizzly.replay.bugzilla ./firefox/firefox <bugid>

Assertion failure: NS_IsMainThread() (Wrong thread!), at /builds/worker/checkouts/gecko/xpcom/threads/nsThreadManager.cpp:248

#0 0x7fffe5b6523b in MOZ_CrashSequence /builds/worker/workspace/obj-build/dist/include/mozilla/Assertions.h:235:3
#1 0x7fffe5b6523b in mozilla::AssertIsOnMainThread() /builds/worker/checkouts/gecko/xpcom/threads/nsThreadManager.cpp:248:31
#2 0x7fffeb5e725f in mozilla::dom::Serial::GetOrCreateManagerChild() /builds/worker/checkouts/gecko/dom/webserial/Serial.cpp:99:3
#3 0x7fffeb5ece7c in GetManagerChildForTesting /builds/worker/checkouts/gecko/dom/webserial/Serial.cpp:778:31
#4 0x7fffeb5ece7c in mozilla::dom::Serial::ResetToDefaultMockDevices(mozilla::ErrorResult&) /builds/worker/checkouts/gecko/dom/webserial/Serial.cpp:877:31
#5 0x7fffe886ae35 in resetToDefaultMockDevices /builds/worker/workspace/obj-build/dom/bindings/./SerialBinding.cpp:1109:60
#6 0x7fffe886ae35 in mozilla::dom::Serial_Binding::resetToDefaultMockDevices_promiseWrapper(JSContext*, JS::Handle<JSObject*>, void*, JSJitMethodCallArgs const&) /builds/worker/workspace/obj-build/dom/bindings/./SerialBinding.cpp:1123:13
#7 0x7fffe918b436 in bool mozilla::dom::binding_detail::GenericMethod<mozilla::dom::binding_detail::NormalThisPolicy, mozilla::dom::binding_detail::ConvertExceptionsToPromises>(JSContext*, unsigned int, JS::Value*) /builds/worker/checkouts/gecko/dom/bindings/BindingUtils.cpp:3398:13
#8 0x7fffede2cc94 in CallJSNative(JSContext*, bool (*)(JSContext*, unsigned int, JS::Value*), js::CallReason, JS::CallArgs const&) /builds/worker/checkouts/gecko/js/src/vm/Interpreter.cpp:488:13
#9 0x7fffede2c53f in js::InternalCallOrConstruct(JSContext*, JS::CallArgs const&, js::MaybeConstruct, js::CallReason) /builds/worker/checkouts/gecko/js/src/vm/Interpreter.cpp:584:12
#10 0x7fffed42a433 in js::jit::DoCallFallback(JSContext*, js::jit::BaselineFrame*, js::jit::ICFallbackStub*, unsigned int, JS::Value*, JS::MutableHandle<JS::Value>) /builds/worker/checkouts/gecko/js/src/jit/BaselineIC.cpp:1699:10
#11 0x37b61e718c7e  ([anon:js-executable-memory]+0xbc7e)

Comment 1

[Greg Stoll :gstoll]

Note that this relies on calling navigator.serial.simulateDeviceConnection(), which is only available if the "dom.webserial.testing.enabled" pref is on.

Comment 2

[Greg Stoll :gstoll]

Attachment: Bug 2036145 - make WebSerial testing methods always run on correct thread r=cmartin!

If the first time we tried to create a SerialManagerChild was on a worker
thread, we would assert. Instead, make the testing methods use the same
pattern as GetPorts() where we make sure to create and access the SerialManagerChild
from the main thread.

Comment 3

[Bugmon [:jkratzer for issues]]

Unable to reproduce bug 2036145 using build mozilla-central 20260413155321-1f396df9f27e. Without a baseline, bugmon is unable to analyze this bug.
Removing bugmon keyword as no further action possible. Please review the bug and re-add the keyword for further analysis.

Comment 4

[Pulsebot]

Pushed by [e-mail]:
https://github.com/mozilla-firefox/firefox/commit/dfad06ec92ec
https://hg.mozilla.org/integration/autoland/rev/1f904357e951
make WebSerial testing methods always run on correct thread r=cmartin

Comment 5

[Serban Stanca [:SerbanS]]

https://hg.mozilla.org/mozilla-central/rev/1f904357e951

Comment 6

[BugBot [:suhaib / :marco]]

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

• If yes, please nominate the patch for beta approval.
  • See https://wiki.mozilla.org/Release_Management/Requesting_an_Uplift for documentation on how to request an uplift.
• If no, please set status-firefox152 to wontfix.

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