loan_cell: add primitive for lending thread-local data #743
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
Add a safe abstraction for temporarily lending on-stack data into thread local storage. Use it in various places across the stack. This fixes a use-after-free in `pal_async`, and it reduces the overhead of TLS in `pal_async` and `underhill_threadpool`.
smalis-msft
reviewed
Jan 30, 2025
smalis-msft
reviewed
Jan 30, 2025
smalis-msft
reviewed
Jan 30, 2025
smalis-msft
reviewed
Jan 30, 2025
smalis-msft
reviewed
Jan 30, 2025
smalis-msft
reviewed
Jan 30, 2025
smalis-msft
reviewed
Jan 30, 2025
smalis-msft
reviewed
Jan 30, 2025
support/loan_cell/src/lib.rs
Outdated
| // call is running, and the value is only dropped when the function | ||
| // passed to `loan` returns. Since `LoadCell` is not `Sync`, this cannot | ||
| // happen while `f` is running. | ||
| let v = unsafe { self.0.get().map(|v| v.as_ref()) }; |
There was a problem hiding this comment.
Can we scope the unsafe brackets to just the as_ref call? Just to make it clear that the only thing unsafe that's happening is the conversion out of the NonNull
|
This change looks reasonable to me after Steven's last comment. Thanks for cleaning this up and fixing it John. |
smalis-msft
previously approved these changes
Jan 30, 2025
smalis-msft
approved these changes
Jan 30, 2025
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Outdated suggestions cannot be applied.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.
Add a safe abstraction for temporarily lending on-stack data into thread local storage. Use it in various places across the stack.
This fixes a use-after-free in
pal_async, and it reduces the overhead of TLS inpal_asyncandunderhill_threadpool.