gh-127521: Mark list as "shared" before resizing if necessary#127524
Uh oh!
There was an error while loading. Please reload this page.
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
In the free threading build, f a non-owning thread resizes a list, it must use QSBR to free the old list array because there may be a concurrent access (without a lock) from the owning thread. To match the pattern in dictobject.c, we just mark the list as "shared" before resizing if it's from a non-owning thread and not already marked as shared.
ContributorAuthor
colesbury commented Dec 2, 2024
The repro from @vstinner no longer crashes: I think there's probably cleaner ways of structuring this, but I figured we might as well match the pattern in dictobject.c for now. We can refactor it a bit later. |
mpage approved these changes Dec 2, 2024
Uh oh!
There was an error while loading. Please reload this page.
colesbury merged commit c7dec02 into python:main 47 checks passed
Uh oh!
There was an error while loading. Please reload this page.
Thanks @colesbury for the PR 🌮🎉.. I'm working now to backport this PR to: 3.13. |
miss-islington pushed a commit to miss-islington/cpython that referenced this pull request Dec 2, 2024
…ythonGH-127524) In the free threading build, if a non-owning thread resizes a list, it must use QSBR to free the old list array because there may be a concurrent access (without a lock) from the owning thread. To match the pattern in dictobject.c, we just mark the list as "shared" before resizing if it's from a non-owning thread and not already marked as shared. (cherry picked from commit c7dec02) Co-authored-by: Sam Gross <[email protected]>
GH-127533 is a backport of this pull request to the 3.13 branch. |
colesbury added a commit that referenced this pull request Dec 3, 2024
…H-127524) (GH-127533) In the free threading build, if a non-owning thread resizes a list, it must use QSBR to free the old list array because there may be a concurrent access (without a lock) from the owning thread. To match the pattern in dictobject.c, we just mark the list as "shared" before resizing if it's from a non-owning thread and not already marked as shared. (cherry picked from commit c7dec02) Co-authored-by: Sam Gross <[email protected]>
Member
vstinner commented Dec 3, 2024
Thanks for the quick fix @colesbury and @mpage! |
colesbury added a commit to colesbury/cpython that referenced this pull request Dec 3, 2024
We were missing locks around some list operations in the free threading build.
colesbury added a commit to colesbury/cpython that referenced this pull request Dec 3, 2024
We were missing locks around some list operations in the free threading build.
colesbury added a commit to colesbury/cpython that referenced this pull request Dec 3, 2024
We were missing locks around some list operations in the free threading build.
srinivasreddy pushed a commit to srinivasreddy/cpython that referenced this pull request Jan 8, 2025
…ython#127524) In the free threading build, if a non-owning thread resizes a list, it must use QSBR to free the old list array because there may be a concurrent access (without a lock) from the owning thread. To match the pattern in dictobject.c, we just mark the list as "shared" before resizing if it's from a non-owning thread and not already marked as shared.
ebonnal pushed a commit to ebonnal/cpython that referenced this pull request Jan 12, 2025
…ython#127524) In the free threading build, if a non-owning thread resizes a list, it must use QSBR to free the old list array because there may be a concurrent access (without a lock) from the owning thread. To match the pattern in dictobject.c, we just mark the list as "shared" before resizing if it's from a non-owning thread and not already marked as shared.
Sign up for freeto join this conversation on GitHub. Already have an account? Sign in to comment
3 participants
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.
In the free threading build, if a non-owning thread resizes a list, it must use QSBR to free the old list array because there may be a concurrent access (without a lock) from the owning thread.
To match the pattern in dictobject.c, we just mark the list as "shared" before resizing if it's from a non-owning thread and not already marked as shared.