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Memory leak due to increasing RetainedMaps size in V8 (Fixed upstream) #57412
Description
Version
v22.14.0
Platform
Linux 5.15.167.4-microsoft-standard-WSL2 #1 SMP Tue Nov 5 00:21:55 UTC 2024 x86_64 x86_64 x86_64 GNU/Linux
Subsystem
v8
What steps will reproduce the bug?
- Run the below script with
--expose-gc. - Wait for some time.
- Check the automatically generated heap snapshots.
- Inspect the following path in the snapshots:
(system) > system / NativeContext > retained_maps :: system / WeakArrayList - Observe that its size keeps increasing over time.
Note:
The increase is gradual, so it may take several hours to see a significant difference.
However, even within a shorter period, a steady increase should still be observable.
const v8 = require('v8');
const ws = new WeakSet();
for (let i = 0; i < 1e10; i++) {
function A() {
this.a = 'a';
this.b = 'b';
this.c = 'c';
}
function B() {
this.a = 'a';
this.b = 'b';
this.c = 'c';
}
function C() {
this.a = 'a';
this.b = 'b';
this.c = 'c';
}
function D() {
this.a = 'a';
this.b = 'b';
this.c = 'c';
}
function E() {
this.a = 'a';
this.b = 'b';
this.c = 'c';
}
const a = new A();
const b = new B();
const c = new C();
const d = new D();
const e = new E();
ws.add(a);
ws.add(b);
ws.add(c);
ws.add(d);
ws.add(e);
gc();
if (i % 10000 === 0) {
v8.writeHeapSnapshot();
}
}How often does it reproduce? Is there a required condition?
It reproduces consistently.
What is the expected behavior? Why is that the expected behavior?
RetainedMaps size should remain stable over time.
What do you see instead?
- The size of RetainedMaps (visible in heap snapshots under (system) > system / NativeContext > retained_maps :: system / WeakArrayList) keeps increasing over time.
- This increase is gradual but persistent, leading to higher memory consumption over extended runtimes.
Eventually, this could result in performance degradation or excessive memory usage.
Below are screenshots showing the memory usage:
v22.14.0
| at startup | after ~9 hours |
|---|---|
 |
 |
v22.14.0 (with the patch applied)
| at startup | after ~5 hours |
|---|---|
 |
 |
Additional information
- This issue started occurring in Node.js 22.0.0 and later, after the following V8 commit was integrated:
e5a29df7b41416de67730d2968c61745b54be66c - The root cause of the issue has been identified and fixed upstream in V8:
V8 Issue 398528460 - I manually applied the fix (Chromium Patch 6330019) to Node.js 22.14.0, built it, and confirmed that the problem was resolved.
Reacted by Juan José, T. Nishino, João Ferreira, Nabeel Bukhari, kahirokunn and Itsuki
Reacted by Juan José, João Ferreira, kahirokunn and Itsuki
Reacted by Juan José, João Ferreira, kahirokunn and Itsuki
Activity
juanarbol commentedon Mar 13, 2025
That's amazing! Could you please send us your patch?
This https://github.com/nodejs/node/blob/main/doc/contributing/maintaining/maintaining-V8.md may be handy
tunamagur0 commentedon Mar 13, 2025
@juanarbol
I'm not entirely sure about the process, but I've created a pull request. Could you please take a look at it when you have a moment?
deps: V8: cherry-pick c172ffc5bf54
deps: V8: cherry-pick c172ffc5bf54
deps: V8: cherry-pick c172ffc5bf54
deps: V8: cherry-pick c172ffc5bf54
schmod commentedon Apr 7, 2025
Was this ever cherry-picked into the 22.x series? I don't see anything in the changelog indicating that it was...
deps: V8: cherry-pick c172ffc5bf54
tunamagur0 commentedon Apr 11, 2025
I think this will be released in the next version.
deps: V8: cherry-pick c172ffc5bf54
deps: V8: cherry-pick c172ffc5bf54
deps: V8: cherry-pick c172ffc5bf54
deps: V8: cherry-pick c172ffc5bf54
deps: V8: cherry-pick c172ffc5bf54
roma2341 commentedon Jun 2, 2025
I am angular dev, node 22.14 version eat tons of RAM (~5-40gb sometimes freezing my OS so i had to do hard reboot), 22.16 version eats ~700 MB, so i think you at least can provide us fix version because "closed ticket" don't answer anything.
updated: issue not fixed in 22.16 my angular dev server still eats 20 gb of ram
joebowbeer commentedon Jul 15, 2026
Cherry picked to 22.x in 22.15
4a852ba