Skip to content

fix(fetch): remove latent cross-thread UB in FetchTasklet shutdown #30943

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
DagmawiKK wants to merge 1 commit into
base: main
Choose a base branch
from
+6 −2
Open

fix(fetch): remove latent cross-thread UB in FetchTasklet shutdown #30943

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
8 changes: 6 additions & 2 deletions src/runtime/webcore/fetch/FetchTasklet.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -378,8 +378,12 @@ impl FetchTasklet {
}
let self_ = Self::from_raw_ref(this);
if self_.javascript_vm.is_shutting_down() {
// SAFETY: last ref; exclusive access
unsafe { FetchTasklet::deinit(this) };
// SAFETY (Intentional Leak): We are on the background HTTP thread.
// During VM shutdown, the JS event loop is dead, so enqueueing a task
// is useless. However, calling `deinit()` synchronously from here is UB:
// it destroys JS-bound handles (`Response::unref` mutating `Cell<u32>`,
// `ReadableStream::Strong`, etc.) off the main JS thread.
// We explicitly abandon this allocation and let the OS reclaim it.
return;
}
// this is really unlikely to happen, but can happen
Expand Down