uefi: Improve handling of null-address allocations in allocate_pages #1558
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
The firmware is allowed to return an allocation at address zero. This is not compatible with Rust, since it's UB to write through a null pointer. If a null address is returned, retry the allocation. If that second allocation still fails, return an error rather than panicking.
|
This seem to match the logic used by GRUB2's AllocatePages wrapper, which has been deployed since the inception of UEFI, so it is probably correct. |
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Outdated suggestions cannot be applied.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.
The firmware is allowed to return an allocation at address zero. This is not compatible with Rust, since it's UB to write through a null pointer. If a null address is returned, retry the allocation. If that second allocation still fails, return an error rather than panicking.
Fixes #1557
Checklist