[Lldb-commits] [lldb] [lldb-dap] Adding support for cancelling a request. (PR #130169)

[Pavel Labath via lldb-commits]

https://github.com/labath commented:

I think there's a race in the cancellation handling:
1. request handling thread sets active_seq (but doesn't start executing the request yet)
2. cancellation request comes in, queue_reader sets the interrupt flag
3. request handling thread begins handling the request, starts by clearing the flag
4. request is not cancelled

I think this would be easier to guarantee correctness (and review) if `active_seq` was *not* an atomic and its modification, as well as the acts of setting and clearing the interrupt flag were done under a mutex

https://github.com/llvm/llvm-project/pull/130169