Clamp Vec::with_capacity to 64KiB to avoid OOM #1545
Merged
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
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Outdated suggestions cannot be applied.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.
Fuzz testers love to muck with length fields and trigger OOM panics. This is documented in #1459.
This PR fixes the linked issue, though my solution is not the suggested one. Rather than adding a new combinator, I've updated
many_m_nandcountto clamp theirVec::with_capacitycalls to 64KiB. This greatly reduces (though does not eliminate) the risk of OOM panics while still providing most of the benefit of preallocating memory.Clamping initial capacity to 64KiB does not affect correctness. Nom will still read the full number of elements. The initial capacity is just a performance hint.