gh-127521: Mark list as "shared" before resizing if necessary #127524
Conversation
This file contains 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.
|
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
|
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 <colesbury@gmail.com>
|
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 <colesbury@gmail.com>
|
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 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.
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.