[gdb/dap] Fix stray KeyboardInterrupt after cancel
When running test-case gdb.dap/pause.exp 100 times in a loop, it passes
100/100.
But if we remove the two "sleep 0.2" from the test-case, we run into
(copied from dap.log and edited for readability):
...
Traceback (most recent call last):
File "startup.py", line 251, in message
def message():
KeyboardInterrupt
Quit
...
This happens as follows.
CancellationHandler.cancel calls gdb.interrupt to cancel a request in flight.
The idea is that this interrupt triggers while in fn here in message (a nested
function of send_gdb_with_response):
...
def message():
try:
val = fn()
result_q.put(val)
except (Exception, KeyboardInterrupt) as e:
result_q.put(e)
...
but instead it triggers outside the try/except.
Fix this by:
- in CancellationHandler, renaming variable in_flight to in_flight_dap_thread,
and adding a variable in_flight_gdb_thread to be able to distinguish when
a request is in flight in the dap thread or the gdb thread.
- adding a wrapper Cancellable to to deal with cancelling the wrapped
event
- using Cancellable in send_gdb and send_gdb_with_response to wrap the posted
event
- in CancellationHandler.cancel, only call gdb.interrupt if
req == self.in_flight_gdb_thread.
This makes the test-case pass 100/100, also when adding the extra stressor of
"taskset -c 0", which makes the fail more likely without the patch.
Tested on aarch64-linux.
Approved-By: Tom Tromey <tom@tromey.com>
PR dap/31275
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=31275
1 file changed
