py/compile: Fix potential Py-stack overflow in try-finally with return. #13569
Conversation
This file contains hidden or 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
If a return is executed within the try block of a try-finally then the return value is stored on the top of the Python stack during the execution of the finally block. In this case the Python stack is one larger than it normally would be in the finally block. Prior to this commit, the compiler was not taking this case into account and could have a Python stack overflow if the Python stack used by the finally block was more than that used elsewhere in the function. In such a scenario the last argument of the function would be clobbered by the top-most temporary value used in the deepest Python expression/statement. This commit fixes that case by making sure enough Python stack is allocated to the function. Fixes issue micropython#13562. Signed-off-by: Damien George <damien@micropython.org>
|
Code size report: |
Codecov ReportAll modified and coverable lines are covered by tests ✅
Additional details and impacted files@@ Coverage Diff @@
## master #13569 +/- ##
=======================================
Coverage 98.36% 98.36%
=======================================
Files 159 159
Lines 21089 21093 +4
=======================================
+ Hits 20744 20748 +4
Misses 345 345 ☔ View full report in Codecov by Sentry. |
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Outdated suggestions cannot be applied.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.
If a return is executed within the try block of a try-finally then the return value is stored on the top of the Python stack during the execution of the finally block. In this case the Python stack is one larger than it normally would be in the finally block.
Prior to this commit, the compiler was not taking this case into account and could have a Python stack overflow if the Python stack used by the finally block was more than that used elsewhere in the function. In such a scenario the last argument of the function would be clobbered by the top-most temporary value used in the deepest Python expression/statement.
This commit fixes that case by making sure enough Python stack is allocated to the function.
Fixes issue #13562.