This is a clear bug in LLDB. If you have a repro case, please file a bug and
attach the instructions on how to make this happen. Our API must be able to
handle things like this.
SBTarget has a shared pointer to a lldb_private::Target. If you have a
reference to a target, it should keep that target alive and it shouldn't crash
later when it is actually freed.
So please file a bug and we'll get it fixed. For a work around for now, yes,
setting all SB references to None should help you work around the issue.
Greg
> On Feb 7, 2016, at 10:41 PM, Jeffrey Tan via lldb-dev
> <lldb-dev@lists.llvm.org> wrote:
>
> Hi,
>
> I have been spending long time troubleshooting a race condition in our lldb
> python test. I finally narrowed down to one code change that caused the race:
> basically, whenever I store SBTarget in DebuggerTestCase's self.target field
> lldb will randomly crash during destruction(see below).
>
> In the code, if I modify the two "self.target" to local variable "target" the
> random crash will disappear.
>
> I am not a python expert. Why is holding SBTarget will cause the test to
> random crash? Do I have to set every SBXXX fields to None before calling
> SBDebugger.Destroy()?
>
>
> ==========================Crash Stack==========================
> Crashed Thread: 0 Dispatch queue: com.apple.main-thread
>
> Exception Type: EXC_BAD_ACCESS (SIGSEGV)
> Exception Codes: KERN_INVALID_ADDRESS at 0x0000000000000010
>
> VM Regions Near 0x10:
> -->
> __TEXT 000000010d145000-000000010d146000 [ 4K] r-x/rwx
> SM=COW
> /System/Library/Frameworks/Python.framework/Versions/2.7/Resources/Python.app/Contents/MacOS/Python
>
> Thread 0 Crashed:: Dispatch queue: com.apple.main-thread
> 0 com.apple.LLDB.framework 0x00000001101c037d
> lldb_private::Listener::BroadcasterWillDestruct(lldb_private::Broadcaster*) +
> 95
> 1 com.apple.LLDB.framework 0x00000001101a0da2
> lldb_private::Broadcaster::Clear() + 50
> 2 com.apple.LLDB.framework 0x00000001101a0ced
> lldb_private::Broadcaster::~Broadcaster() + 75
> 3 com.apple.LLDB.framework 0x00000001103d6879
> lldb_private::Target::~Target() + 741
> 4 com.apple.LLDB.framework 0x00000001103d6c20
> lldb_private::Target::~Target() + 14
> 5 libc++.1.dylib 0x00007fff896448a6
> std::__1::__shared_weak_count::__release_shared() + 44
> 6 com.apple.LLDB.framework 0x000000010e560664
> _wrap_delete_SBTarget(_object*, _object*) + 123
> 7 org.python.python 0x000000010d15a50a PyObject_Call + 99
>
>
> ==========================Code==========================
> from find_lldb import lldb
> from simplest_event_thread import LLDBListenerThread
> import unittest
> import threading
>
> running_signal = threading.Event()
> stopped_signal = threading.Event()
>
> def launch_debugging(debugger, stop_at_entry):
> error = lldb.SBError()
> listener = lldb.SBListener('Chrome Dev Tools Listener')
> target = debugger.GetSelectedTarget()
> process = target.Launch (listener,
> None, # argv
> None, # envp
> None, # stdin_path
> None, # stdout_path
> None, # stderr_path
> None, # working directory
> 0, # launch flags
> stop_at_entry, # Stop at entry
> error) # error
> print 'Launch result: %s' % str(error)
>
> event_thread = LLDBListenerThread(debugger, running_signal,
> stopped_signal)
> event_thread.start()
>
> running_signal.set()
> return event_thread
>
> class DebuggerTestCase:
>
> def wait_for_process_stop(self):
> running_signal.wait()
> running_signal.clear()
> stopped_signal.wait()
> stopped_signal.clear()
>
> def test_breakpoint_at_line(self):
> debugger = lldb.SBDebugger.Create()
> debugger.SetAsync(True)
> executable_path =
> '~/Personal/compiler/CompilerConstruction/code/compiler'
> self.target = debugger.CreateTargetWithFileAndArch(executable_path,
> lldb.LLDB_ARCH_DEFAULT)
>
> event_thread = launch_debugging(debugger, stop_at_entry=True)
>
> process = debugger.GetSelectedTarget().process
> self.wait_for_process_stop() # wait for entry breakpoint.
> self.target.BreakpointCreateByName('main')
> process.Continue()
> self.wait_for_process_stop() # wait for main breakpoint.
>
> event_thread.should_quit = True
> event_thread.join()
> lldb.SBDebugger.Destroy(debugger)
>
> if __name__ == '__main__':
> test = DebuggerTestCase()
> for i in range(20):
> test.test_breakpoint_at_line()
> _______________________________________________
> lldb-dev mailing list
> lldb-dev@lists.llvm.org
> http://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-dev
_______________________________________________
lldb-dev mailing list
lldb-dev@lists.llvm.org
http://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-dev
