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Nonsense UNKNOWN error when writing large buffers with fs.writev #40779

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#65736
Open
Nonsense UNKNOWN error when writing large buffers with fs.writev#40779
#65736
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fsIssues and PRs related to file-system APIs and the fs module.staleIssues and PRs marked stale due to inactivity and scheduled for automatic closure.

Description

@zbjornson
zbjornson
opened on Nov 10, 2021

Version

14.18.1

Platform

Linux ops 5.11.0-1021-gcp #23~20.04.1-Ubuntu SMP Fri Oct 1 19:04:32 UTC 2021 x86_64 x86_64 x86_64 GNU/Linu

Subsystem

fs

What steps will reproduce the bug?

const fs = require("fs");
const fd = fs.openSync("./test.dat", fs.constants.O_WRONLY | fs.constants.O_CREAT, 0o666);
const bufs = [Buffer.alloc(0x7FFFFFFF + 1)];
fs.writevSync(fd, bufs, 0);

This throws

Uncaught Error: UNKNOWN: unknown error, write
    at Object.writevSync (fs.js:749:3) {
  errno: -2147483648,
  syscall: 'write',
  code: 'UNKNOWN'
}

That errno is 0x7fffffff + 1 wrapped around.

How often does it reproduce? Is there a required condition?

Always.

What is the expected behavior?

Should either work, since pwritev(2) works (I don't know if it has a limit less than SSIZE_MAX), or report a proper error before making the syscall. I did the latter recently for fs.write in c4e7dca. It would be nice if large files actually worked, but the best fix for that would require a new libuv function.

What do you see instead?

No response

Additional information

No response

Activity

  1. VoltrexKeyva
    added
    fsIssues and PRs related to file-system APIs and the fs module.
    on Nov 10, 2021

  2. github-actions commented on Jun 26, 2026

    @github-actions
    github-actionsbot
    on Jun 26, 2026 – with GitHub Actions
    Contributor

    This issue has been marked as stale due to 210 days of inactivity.
    It will be automatically closed in 30 days if no further activity occurs. If this is still relevant, please leave a comment or update it to keep it open.

  3. github-actions
    added
    staleIssues and PRs marked stale due to inactivity and scheduled for automatic closure.
    on Jun 26, 2026

  4. zbjornson commented on Jun 27, 2026

    @zbjornson
    zbjornson
    on Jun 27, 2026
    ContributorAuthor

    Still relevant, and I see related upstream activity in libuv in March!

  5. github-actions
    removed
    staleIssues and PRs marked stale due to inactivity and scheduled for automatic closure.
    on Jun 27, 2026

  6. github-actions commented on Sep 26, 2026

    @github-actions
    github-actionsbot
    on Sep 26, 2026 – with GitHub Actions
    Contributor

    This issue has been marked as stale due to 90 days of inactivity.
    It will be automatically closed in 30 days if no further activity occurs. If this is still relevant, please leave a comment or update it to keep it open.

  7. github-actions
    added
    staleIssues and PRs marked stale due to inactivity and scheduled for automatic closure.
    on Sep 26, 2026
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