[Lldb-commits] [lldb] 8a3597d - [lldb] Fix CommandInterpreter::DidProcessStopAbnormally() with multiple threads

[Martin Storsjö via lldb-commits]

Author: Martin Storsjö
Date: 2022-09-26T11:05:42+03:00
New Revision: 8a3597d73c8f694ca8c991d8cb4bb97a4ac8ba8c

URL: https://github.com/llvm/llvm-project/commit/8a3597d73c8f694ca8c991d8cb4bb97a4ac8ba8c
DIFF: https://github.com/llvm/llvm-project/commit/8a3597d73c8f694ca8c991d8cb4bb97a4ac8ba8c.diff

LOG: [lldb] Fix CommandInterpreter::DidProcessStopAbnormally() with multiple threads

If a process has multiple threads, the thread with the stop
info might not be the first one in the thread list.

On Windows, under certain circumstances, processes seem to have
one or more extra threads that haven't been launched by the
executable itself, waiting in NtWaitForWorkViaWorkerFactory. If the
main (stopped) thread isn't the first one in the list (the order
seems nondeterministic), DidProcessStopAbnormally() would return
false prematurely, instead of inspecting later threads.

The main observable effect of DidProcessStopAbnormally() erroneously
returning false, is when running lldb with multiple "-o" parameters
to specify multiple commands to execute on the command line.

After an abnormal stop, lldb would stop executing "-o" parameters
and execute "-k" parameters instead - but due to this issue, it
would instead keep executing "-o" parameters as if there was no
abnormal stop. (If multiple parameters are specified via a script
file via the "-s" option, all of the commands in that file are
executed regardless of whether there's an abnormal stop inbetween.)

Differential Revision: https://reviews.llvm.org/D134037

Added: 
    lldb/test/Shell/Driver/CommandOnCrashMultiThreaded.test
    lldb/test/Shell/Driver/Inputs/CommandOnCrashMultiThreaded.cpp

Modified: 
    lldb/source/Interpreter/CommandInterpreter.cpp

Removed: 
    


################################################################################
diff  --git a/lldb/source/Interpreter/CommandInterpreter.cpp b/lldb/source/Interpreter/CommandInterpreter.cpp
index fa6511635e287..5c11b87dcbe03 100644
--- a/lldb/source/Interpreter/CommandInterpreter.cpp
+++ b/lldb/source/Interpreter/CommandInterpreter.cpp
@@ -2471,8 +2471,12 @@ bool CommandInterpreter::DidProcessStopAbnormally() const {
 
   for (const auto &thread_sp : process_sp->GetThreadList().Threads()) {
     StopInfoSP stop_info = thread_sp->GetStopInfo();
-    if (!stop_info)
-      return false;
+    if (!stop_info) {
+      // If there's no stop_info, keep iterating through the other threads;
+      // it's enough that any thread has got a stop_info that indicates
+      // an abnormal stop, to consider the process to be stopped abnormally.
+      continue;
+    }
 
     const StopReason reason = stop_info->GetStopReason();
     if (reason == eStopReasonException ||

diff  --git a/lldb/test/Shell/Driver/CommandOnCrashMultiThreaded.test b/lldb/test/Shell/Driver/CommandOnCrashMultiThreaded.test
new file mode 100644
index 0000000000000..b16cfc5763715
--- /dev/null
+++ b/lldb/test/Shell/Driver/CommandOnCrashMultiThreaded.test
@@ -0,0 +1,5 @@
+# REQUIRES: native && (target-x86 || target-x86_64)
+# RUN: %clangxx_host %p/Inputs/CommandOnCrashMultiThreaded.cpp -o %t -pthread
+# RUN: %lldb -b -o "process launch" -k "process continue" -k "exit" %t | FileCheck %s
+
+# CHECK: Process {{[0-9]+}} exited with status = 0

diff  --git a/lldb/test/Shell/Driver/Inputs/CommandOnCrashMultiThreaded.cpp b/lldb/test/Shell/Driver/Inputs/CommandOnCrashMultiThreaded.cpp
new file mode 100644
index 0000000000000..f469d82fbbef9
--- /dev/null
+++ b/lldb/test/Shell/Driver/Inputs/CommandOnCrashMultiThreaded.cpp
@@ -0,0 +1,13 @@
+#include <thread>
+
+void t_func() {
+  asm volatile(
+    "int3\n\t"
+  );
+}
+
+int main() {
+  std::thread t(t_func);
+  t.join();
+  return 0;
+}