Fix parking lot hash table after fork #6963
Draft
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
Contributor
|
Important Review skippedDraft detected. Please check the settings in the CodeRabbit UI or the You can disable this status message by setting the
✨ Finishing touches🧪 Generate unit tests (beta)
Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out. Comment |
youknowone
force-pushed
the
fork-safety
branch
from
d95e4ab to
b516c63
Compare
This was referenced Feb 2, 2026
Merged
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
1 participant
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Outdated suggestions cannot be applied.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.
parking_lot_core maintains a global hash table (HASHTABLE) mapping lock addresses to queues of parked threads. Each bucket holds a linked list of ThreadData pointers.
fork() copies all memory but only one thread survives in the child. The hash table still references ThreadData of the dead threads, WordLocks held by them will never be released, and queue pointers become stale. When the child later hits a contended lock, park() follows these stale pointers and segfaults.
parking_lot_core currently has no such handling for child process
Issue reported to parking_lot Amanieu/parking_lot#515