1940692 - Linux arm64 startup Crash in [@ js::gc::CheckDecommit]

Status: RESOLVED FIXED

(Core :: JavaScript: GC, defect, P1)

Description

[Sebastian Hengst [:aryx] (needinfo me if it's about an intermittent or backout)]

33 crashes from 7+ installs of Firefox 136.0a1 with lowest build ID 20250108093633. CPU architecture is arm64, OS is Linux, often Fedora Linux Asahi. The crash is registered on startup.

Regression from bug 1934856?

Crash report: https://crash-stats.mozilla.org/report/index/119c4041-c9df-4fe8-9612-66d380250109

MOZ_CRASH Reason:

MOZ_RELEASE_ASSERT(OffsetFromAligned(region, pageSize) == 0)

Top 10 frames:

0  libxul.so  js::gc::CheckDecommit(void*, unsigned long)  js/src/gc/Memory.cpp:831
0  libxul.so  js::gc::MarkPagesUnusedSoft(void*, unsigned long)  js/src/gc/Memory.cpp:837
1  libxul.so  js::gc::BufferAllocator::addSweptRegion(js::gc::BufferChunk*, unsigned long, ...  js/src/gc/BufferAllocator.cpp:1833
2  libxul.so  js::gc::BufferAllocator::sweepChunk(js::gc::BufferChunk*, js::gc::BufferAlloc...  js/src/gc/BufferAllocator.cpp:1803
3  libxul.so  js::gc::BufferAllocator::sweepForMajorCollection(bool)  js/src/gc/BufferAllocator.cpp:1109
4  libxul.so  js::gc::GCRuntime::sweepBackgroundThings(js::gc::ZoneList&)  js/src/gc/Sweeping.cpp:400
4  libxul.so  js::gc::GCRuntime::sweepFromBackgroundThread(js::AutoLockHelperThreadState&)  js/src/gc/Sweeping.cpp:453
4  libxul.so  js::gc::BackgroundSweepTask::run(js::AutoLockHelperThreadState&)  js/src/gc/Sweeping.cpp:444
5  libxul.so  js::GCParallelTask::runTask(JS::GCContext*, js::AutoLockHelperThreadState&)  js/src/gc/GCParallelTask.cpp:218
6  libxul.so  js::GCParallelTask::runFromMainThread(js::AutoLockHelperThreadState&)  js/src/gc/GCParallelTask.cpp:174

Comment 1

[Jon Coppeard (:jonco)]

Bug 1934856 broke arm64 Linux on Apple hardware and other systems where the system page size doesn't match the compiled in value.

Comment 2

[Jon Coppeard (:jonco)]

Attachment: Bug 1940692 - Part 1: Don't decommit any buffer memory if decommit is disabled r?sfink

Comment 3

[Jon Coppeard (:jonco)]

Attachment: Bug 1940692 - Part 2: Add a test that collects buffers with decommit disabled r?sfink

This required adding a way of disabling decommit in the shell.

Comment 6

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

The bug is linked to a topcrash signature, which matches the following criterion:

• Top 10 desktop browser crashes on nightly (startup)

For more information, please visit BugBot documentation.

Comment 7

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/e3f2eed01249
Part 1: Don't decommit any buffer memory if decommit is disabled r=sfink
https://hg.mozilla.org/integration/autoland/rev/c4f26c26393a
Part 2: Add a test that collects buffers with decommit disabled r=sfink

Comment 8

[Norisz Fay [:noriszfay]]

https://hg.mozilla.org/mozilla-central/rev/e3f2eed01249
https://hg.mozilla.org/mozilla-central/rev/c4f26c26393a