We got user reporting lldb crash while the debuggee is calling vfork()
concurrently from multiple threads.
The crash happens because the current implementation can only handle
single vfork, vforkdone protocol transaction.
This diff fixes the crash by lldb-server storing forked debuggee's <pid,
tid> pair in jstopinfo which will be decoded by lldb client to create
StopInfoVFork for follow parent/child policy. Each StopInfoVFork will
later have a corresponding vforkdone packet. So the patch also changes
the `m_vfork_in_progress` to be reference counting based.
Two new test cases are added which crash/assert without the changes in
this patch.
---------
Co-authored-by: jeffreytan81 <jeffreytan@fb.com>
This is an ongoing series of commits that are reformatting our Python
code. Reformatting is done with `black` (23.1.0).
If you end up having problems merging this commit because you have made
changes to a python file, the best way to handle that is to run `git
checkout --ours <yourfile>` and then reformat it with black.
RFC: https://discourse.llvm.org/t/rfc-document-and-standardize-python-code-style
Differential revision: https://reviews.llvm.org/D151460
Step over thread plans were claiming to explain the fork stop reasons,
which prevented the default fork logic (detaching from the child
process) from kicking in. This patch changes that.
Differential Revision: https://reviews.llvm.org/D141605
