[all-commits] [llvm/llvm-project] bb9006: [lldb] Fix data race in ThreadList

[Augusto Noronha via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: bb90063249707e3ae081bfbd8e3512566abb7df6
      https://github.com/llvm/llvm-project/commit/bb90063249707e3ae081bfbd8e3512566abb7df6
  Author: Augusto Noronha <augusto2112 at me.com>
  Date:   2023-08-18 (Fri, 18 Aug 2023)

  Changed paths:
    M lldb/include/lldb/Target/Process.h
    M lldb/include/lldb/Target/ThreadCollection.h
    M lldb/include/lldb/Target/ThreadList.h
    M lldb/source/Target/Process.cpp
    M lldb/source/Target/ThreadList.cpp

  Log Message:
  -----------
  [lldb] Fix data race in ThreadList

ThreadSanitizer reports the following issue:

```
  Write of size 8 at 0x00010a70abb0 by thread T3 (mutexes: write M0):
    #0 lldb_private::ThreadList::Update(lldb_private::ThreadList&) ThreadList.cpp:741 (liblldb.18.0.0git.dylib:arm64+0x5dedf4) (BuildId: 9bced2aafa373580ae9d750d9cf79a8f32000000200000000100000000000e00)
    #1 lldb_private::Process::UpdateThreadListIfNeeded() Process.cpp:1212 (liblldb.18.0.0git.dylib:arm64+0x53bbec) (BuildId: 9bced2aafa373580ae9d750d9cf79a8f32000000200000000100000000000e00)

  Previous read of size 8 at 0x00010a70abb0 by main thread (mutexes: write M1):
    #0 lldb_private::ThreadList::GetMutex() const ThreadList.cpp:785 (liblldb.18.0.0git.dylib:arm64+0x5df138) (BuildId: 9bced2aafa373580ae9d750d9cf79a8f32000000200000000100000000000e00)
    #1 lldb_private::ThreadList::DidResume() ThreadList.cpp:656 (liblldb.18.0.0git.dylib:arm64+0x5de5c0) (BuildId: 9bced2aafa373580ae9d750d9cf79a8f32000000200000000100000000000e00)
    #2 lldb_private::Process::PrivateResume() Process.cpp:3130 (liblldb.18.0.0git.dylib:arm64+0x53cd7c) (BuildId: 9bced2aafa373580ae9d750d9cf79a8f32000000200000000100000000000e00)
```

Fix this by only using the mutex in ThreadList and removing the one in
process entirely.

Differential Revision: https://reviews.llvm.org/D158034