[all-commits] [llvm/llvm-project] dbc40b: [lldb] Fix the flakey Concurrent tests on macOS (#...

[Jason Molenda via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: dbc40b34617b5ee5d2f82272c8863c602265063c
      https://github.com/llvm/llvm-project/commit/dbc40b34617b5ee5d2f82272c8863c602265063c
  Author: Jason Molenda <jmolenda at apple.com>
  Date:   2024-02-14 (Wed, 14 Feb 2024)

  Changed paths:
    M lldb/packages/Python/lldbsuite/test/concurrent_base.py

  Log Message:
  -----------
  [lldb] Fix the flakey Concurrent tests on macOS (#81710)

The concurrent tests all do a pthread_join at the end, and
concurrent_base.py stops after that pthread_join and sanity checks that
only 1 thread is running. On macOS, after pthread_join() has completed,
there can be an extra thread still running which is completing the
details of that task asynchronously; this causes testsuite failures.
When this happens, we see the second thread is in

```
frame #0: 0x0000000180ce7700 libsystem_kernel.dylib`__ulock_wake + 8
frame #1: 0x0000000180d25ad4 libsystem_pthread.dylib`_pthread_joiner_wake + 52
frame #2: 0x0000000180d23c18 libsystem_pthread.dylib`_pthread_terminate + 384
frame #3: 0x0000000180d23a98 libsystem_pthread.dylib`_pthread_terminate_invoke + 92
frame #4: 0x0000000180d26740 libsystem_pthread.dylib`_pthread_exit + 112
frame #5: 0x0000000180d26040 libsystem_pthread.dylib`_pthread_start + 148
```

there are none of the functions from the test file present on this
thread.

In this patch, instead of counting the number of threads, I iterate over
the threads looking for functions from our test file (by name) and only
count threads that have at least one of them.

It's a lower frequency failure than the darwin kernel bug causing an
extra step instruction mach exception when hardware
breakpoint/watchpoints are used, but once I fixed that, this came up as
the next most common failure for these tests.

rdar://110555062