add debug_assert in case pos > cap for copy_bidirectional #4125
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
Darksonn
reviewed
Sep 22, 2021
tokio/src/io/util/copy.rs
Outdated
| // If pos larger than cap, this loop will never stop. | ||
| // In particular, user's wrong poll_write implementation returning | ||
| // incorrect written length may lead to thread blocking. | ||
| debug_assert!(self.pos <= self.cap, "pos should never larger than cap"); |
There was a problem hiding this comment.
Seems like we should give the user an better error message.
Suggested change
| debug_assert!(self.pos <= self.cap, "pos should never larger than cap"); | |
| debug_assert!(self.pos <= self.cap, "writer returned length larger than input slice"); |
Darksonn
approved these changes
Sep 22, 2021
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Outdated suggestions cannot be applied.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.
Motivation
Wrong poll_write implementation may lead to thread blocking.
e.g., poll_write returns written length larger than cap. When reader connection alive, thread will stuck in buf_copy.
Solution
This is hard to debug, maybe add a
debug_assert!will help.