While working (mostly cargo check) on polkadot I've stumbled on a problem where the kusama-runtime (only it) build hangs. According to cargo build -vv kusama-runtime starts building in the very start and the waits for the lock on build directory.

Here is the excerpt

[kusama-runtime 0.8.25]     Blocking waiting for file lock on package cache
[rococo-v1-runtime 0.8.25]     Blocking waiting for file lock on package cache
[polkadot-test-runtime 0.8.25]     Blocking waiting for file lock on package cache
[polkadot-runtime 0.8.25]     Blocking waiting for file lock on package cache
[westend-runtime 0.8.25]     Blocking waiting for file lock on package cache
[kusama-runtime 0.8.25]     Blocking waiting for file lock on build directory

Apparently, it never actually releases this lock. Removing wbuild and wbuild-runner didn't help and has lead to inclusion failures. Removing locks across the target directory didn't help as well, but probably I missed the right one.

cargo clean saved the day, but it's really annoying to wait for the rebuild.