fix(hiding_ci): race condition in write syscall #5338
Closed
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Codecov Report✅ All modified and coverable lines are covered by tests. Additional details and impacted files@@ Coverage Diff @@
## feature/secret-hiding #5338 +/- ##
======================================================
Coverage 81.94% 81.94%
======================================================
Files 250 250
Lines 27612 27612
======================================================
Hits 22626 22626
Misses 4986 4986
Flags with carried forward coverage won't be shown. Click here to find out more. ☔ View full report in Codecov by Sentry. 🚀 New features to boost your workflow:
|
roypat
reviewed
Jul 31, 2025
| + *offset += PAGE_SIZE; | ||
| + } | ||
| + else | ||
| + filemap_remove_folio(folio); |
There was a problem hiding this comment.
In this scenario, I think we need to return 0 instead of copied, because we're throwing away the data written
There was a problem hiding this comment.
good point, fixed, thanks!
Do this by implementing write_iter instead that takes care about folio locking and potential prefaulting of the user buffer. Signed-off-by: Nikita Kalyazin <[email protected]>
|
picked up as part of #5340 |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Changes
Fix a race condition in the write syscall by implementing write_iter instead that takes care about folio locking and potential prefaulting of the user buffer.
Reason
The original write implementation was dropping the folio lock before copying the data in which was leading to a race with the fault handler that was being able to start clearing the page when the write was already writing to it.
License Acceptance
By submitting this pull request, I confirm that my contribution is made under
the terms of the Apache 2.0 license. For more information on following Developer
Certificate of Origin and signing off your commits, please check
CONTRIBUTING.md.PR Checklist
tools/devtool checkstyleto verify that the PR passes theautomated style checks.
how they are solving the problem in a clear and encompassing way.
[ ] I have updated any relevant documentation (both in code and in the docs)in the PR.
[ ] I have mentioned all user-facing changes inCHANGELOG.md.[ ] If a specific issue led to this PR, this PR closes the issue.[ ] When making API changes, I have followed theRunbook for Firecracker API changes.
[ ] I have tested all new and changed functionalities in unit tests and/orintegration tests.
[ ] I have linked an issue to every newTODO.rust-vmm.