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GeezerVison is showing github.com — fs: keep readFile abortable on non-regular files by christianaurichzm · Pull Request #66940 · nodejs/node

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@christianaurichzm

@christianaurichzm christianaurichzm commented Oct 23, 2026

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fs.readFile() and fs.promises.readFile() ignore an AbortSignal on FIFOs and devices. The read only ends at EOF, so on a FIFO whose writer stays open the abort waits for the writer to close, and on /dev/zero it never ends:

const ac = new AbortController();
setTimeout(() => ac.abort(), 100);
require('fs').promises.readFile('/dev/zero', { signal: ac.signal })
  .catch((err) => console.log(err.name));

v22.23.1 prints AbortError after 100 ms. On main it never does, and memory grows until the process is killed (after 1 s with a 2 GiB limit).

Since #65327, ReadFileJob reads a non-regular file to EOF in one thread pool job and only checks the signal when the job is done. Files over one chunk already go back to the chunked reader, which checks it before each read. Send non-regular files there as well. Regular files that report size 0, like the ones in procfs, are still read in one job. Only v26.8.0+ is affected.

The new test aborts a read on a FIFO and checks that the reader closes it while the writer is still open. It fails on main for both APIs and passes with the fix. fs tests, C++ lint/format and ESLint pass on Linux x64.

Refs: #65327

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@christianaurichzm
fs: keep readFile abortable on non-regular files
10ebd2a 
`ReadFileJob` treats a file that is not a regular file as size 0 and
reads it to EOF inside one thread pool job, so the `AbortSignal` is
only checked once the job ends. `fs.readFile()` and
`fs.promises.readFile()` on a FIFO whose writer stays open therefore
do not settle until the writer closes, and on `/dev/zero` they keep
growing the buffer until the process runs out of memory.

Hand the fd back to the chunked reader for non-regular files, the path
files larger than one chunk already take. It checks the signal before
each read. Regular files that report size 0, such as procfs files, are
still read in one job.

Signed-off-by: Christian Aurich Zanettini Martins <[email protected]>
@nodejs-github-bot nodejs-github-bot added c++ Issues and PRs that require attention from people who are familiar with C++. fs Issues and PRs related to file-system APIs and the fs module. needs-ci PRs that need a full CI run. labels Oct 23, 2026
@codecov

codecov Bot commented Oct 23, 2026 •
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Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 90.59%. Comparing base (44d5d57) to head (10ebd2a).
⚠️ Report is 239 commits behind head on main.

Additional details and impacted files 
@@            Coverage Diff             @@
##             main   #66940      +/-   ##
==========================================
+ Coverage   90.57%   90.59%   +0.01%     
==========================================
  Files         797      797              
  Lines      278502   278278     -224     
  Branches    53538    53504      -34     
==========================================
- Hits       252267   252106     -161     
+ Misses      16576    16542      -34     
+ Partials     9659     9630      -29
Files with missing lines Coverage Δ
lib/fs.js 97.17% <100.00%> (+<0.01%) ⬆️
lib/internal/fs/promises.js 91.63% <100.00%> (+0.41%) ⬆️
src/node_file.cc 75.69% <100.00%> (-0.20%) ⬇️

... and 31 files with indirect coverage changes

🚀 New features to boost your workflow:
  • ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
  • 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.
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@christianaurichzm

christianaurichzm commented Oct 23, 2026

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@codebytere @jasnell, this follows up on #65327, could you take a look? If it looks good, could you also add request-ci? Thanks!

cc @panva
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addaleax
addaleax approved these changes Oct 30, 2026
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@addaleax addaleax added author ready PRs with CI started, the required approvals, and no outstanding review comments. request-ci Add this label to start a Jenkins CI on a PR. Only starts once the PR has an approving review. labels Oct 30, 2026
@github-actions github-actions Bot removed the request-ci Add this label to start a Jenkins CI on a PR. Only starts once the PR has an approving review. label Oct 30, 2026
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nodejs-github-bot commented Oct 30, 2026

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CI: https://ci.nodejs.org/job/node-test-pull-request/78744/
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@nodejs-github-bot

nodejs-github-bot commented Oct 31, 2026

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CI: https://ci.nodejs.org/job/node-test-pull-request/78764/
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@christianaurichzm christianaurichzm added the commit-queue PRs queued for automated landing through the Commit Queue. label Nov 10, 2026
@nodejs-github-bot
nodejs-github-bot merged commit 6c8a697 into nodejs:main Nov 10, 2026
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Landed in 6c8a697
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@nodejs-github-bot nodejs-github-bot removed the commit-queue PRs queued for automated landing through the Commit Queue. label Nov 10, 2026
aduh95 pushed a commit that referenced this pull request Nov 11, 2026
@christianaurichzm @aduh95
fs: keep readFile abortable on non-regular files
0c5be92 
`ReadFileJob` treats a file that is not a regular file as size 0 and
reads it to EOF inside one thread pool job, so the `AbortSignal` is
only checked once the job ends. `fs.readFile()` and
`fs.promises.readFile()` on a FIFO whose writer stays open therefore
do not settle until the writer closes, and on `/dev/zero` they keep
growing the buffer until the process runs out of memory.

Hand the fd back to the chunked reader for non-regular files, the path
files larger than one chunk already take. It checks the signal before
each read. Regular files that report size 0, such as procfs files, are
still read in one job.

Signed-off-by: Christian Aurich Zanettini Martins <[email protected]>
PR-URL: #66940
Refs: #65327
Reviewed-By: Anna Henningsen <[email protected]>
@github-actions github-actions Bot mentioned this pull request Nov 11, 2026
2026-11-12, Version 27.0.0-alpha.0.1.0 (Alpha) #67415
Merged
aduh95 pushed a commit that referenced this pull request Nov 12, 2026
@christianaurichzm @aduh95
fs: keep readFile abortable on non-regular files
3c5f22b 
`ReadFileJob` treats a file that is not a regular file as size 0 and
reads it to EOF inside one thread pool job, so the `AbortSignal` is
only checked once the job ends. `fs.readFile()` and
`fs.promises.readFile()` on a FIFO whose writer stays open therefore
do not settle until the writer closes, and on `/dev/zero` they keep
growing the buffer until the process runs out of memory.

Hand the fd back to the chunked reader for non-regular files, the path
files larger than one chunk already take. It checks the signal before
each read. Regular files that report size 0, such as procfs files, are
still read in one job.

Signed-off-by: Christian Aurich Zanettini Martins <[email protected]>
PR-URL: #66940
Refs: #65327
Reviewed-By: Anna Henningsen <[email protected]>
aduh95 pushed a commit that referenced this pull request Nov 12, 2026
@christianaurichzm @aduh95
fs: keep readFile abortable on non-regular files
d59e71d 
`ReadFileJob` treats a file that is not a regular file as size 0 and
reads it to EOF inside one thread pool job, so the `AbortSignal` is
only checked once the job ends. `fs.readFile()` and
`fs.promises.readFile()` on a FIFO whose writer stays open therefore
do not settle until the writer closes, and on `/dev/zero` they keep
growing the buffer until the process runs out of memory.

Hand the fd back to the chunked reader for non-regular files, the path
files larger than one chunk already take. It checks the signal before
each read. Regular files that report size 0, such as procfs files, are
still read in one job.

Signed-off-by: Christian Aurich Zanettini Martins <[email protected]>
PR-URL: #66940
Refs: #65327
Reviewed-By: Anna Henningsen <[email protected]>
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@christianaurichzm @nodejs-github-bot @addaleax
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