Skip to content

gh-114944: Fix race between _PyParkingLot_Park and _PyParkingLot_UnparkAll when handling interrupts #114945

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

Merged
merged 4 commits into from
Feb 5, 2024
Merged

gh-114944: Fix race between _PyParkingLot_Park and _PyParkingLot_UnparkAll when handling interrupts #114945

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
4 commits
Select commit Hold shift + click to select a range
d68bf0d
Fix race between `_PyParkingLot_Park` and `_PyParkingLot_UnparkAll` w…
mpage Feb 3, 2024
cd85723
📜🤖 Added by blurb_it.
blurb-it[bot] Feb 3, 2024
33fea69
Set `is_unparking` in dequeue{_all}
mpage Feb 3, 2024
b06247d
Move node declaration back
mpage Feb 3, 2024
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
1 change: 1 addition & 0 deletions Misc/NEWS.d/next/Core and Builtins/2024-02-03-01-48-38.gh-issue-114944.4J5ELD.rst
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1 @@
Fixes a race between ``PyParkingLot_Park`` and ``_PyParkingLot_UnparkAll``.
4 changes: 2 additions & 2 deletions Python/parking_lot.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -244,6 +244,7 @@ dequeue(Bucket *bucket, const void *address)
if (wait->addr == (uintptr_t)address) {
llist_remove(node);
--bucket->num_waiters;
wait->is_unparking = true;
return wait;
}
}
Expand All @@ -262,6 +263,7 @@ dequeue_all(Bucket *bucket, const void *address, struct llist_node *dst)
llist_remove(node);
llist_insert_tail(dst, node);
--bucket->num_waiters;
wait->is_unparking = true;
}
}
}
Expand Down Expand Up @@ -337,8 +339,6 @@ _PyParkingLot_Unpark(const void *addr, _Py_unpark_fn_t *fn, void *arg)
_PyRawMutex_Lock(&bucket->mutex);
struct wait_entry *waiter = dequeue(bucket, addr);
if (waiter) {
waiter->is_unparking = true;

int has_more_waiters = (bucket->num_waiters > 0);
fn(arg, waiter->park_arg, has_more_waiters);
}
Expand Down