Don't clear the context stack in pop #14
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
Currently, when pop returns, the stack is deinitialized if empty. I assume this is an optimize to free memory ASAP, without having to wait for deinit. But currently, the only way to free a Ctx is from a callback being executed within pop. You have to call `ctx.deinit` within `ctx.pop`, and you possibly have other things to clean up too, like deallocating a heap-allocated Ctx. This makes _any_ operations after @call returns dangerous. Consider this code: https://github.com/lightpanda-io/browser/blob/6ae4ed9fc33eb82d7206d52692d8616737d11bf5/src/xhr/xhr.zig#L617 This calls ctx.deinit() _within_ a call to ctx.pop, it then sets the union referencing ctx to null. After that point, the ctx variable/memory should not be used.
krichprollsch
approved these changes
Mar 4, 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Outdated suggestions cannot be applied.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.
Currently, when pop returns, the stack is deinitialized if empty. I assume this is an optimize to free memory ASAP, without having to wait for deinit.
But currently, the only way to free a Ctx is from a callback being executed within pop. You have to call
ctx.deinitwithinctx.pop, and you possibly have other things to clean up too, like deallocating a heap-allocated Ctx. This makes any operations after @call returns dangerous.Consider this code:
https://github.com/lightpanda-io/browser/blob/6ae4ed9fc33eb82d7206d52692d8616737d11bf5/src/xhr/xhr.zig#L617
This calls ctx.deinit() within a call to ctx.pop, it then sets the union referencing ctx to null. After that point, the ctx variable/memory should not be used.