jingham created this revision.
jingham added a reviewer: clayborg.
Herald added a project: LLDB.
Herald added a subscriber: lldb-commits.
When talking to a gdb-remote server that didn't support the newer thread info
packets, we noticed that lldb would hit a breakpoint in target, but then
continue on without stopping. This was because the only indication of why you
stopped in this scenario was the initial "T05thread:01;" packet.
Unfortunately, lldb read the stop reasons from the stop packet and created the
new thread & set its stop reason BEFORE calling UpdateThreadListIfNeeded. So
when you finally got around to calling UpdateThreadListIfNeeded, we would
notice that the ThreadList StopID was out of date, wipe the stop reasons, and
then update. Normally some other thread info packet would tell us the stop
reason again, and we we'd get back on track. But if they weren't supported,
we'd be left thinking that the process had stopped for no reason, and
auto-continue it.
The main part of the patch just adjusts the call to UpdateThreadListIfNeeded so
it happens before we try to set StopInfo's.
I also added a test that captures this failure.
Repository:
rLLDB LLDB
https://reviews.llvm.org/D62887
Files:
packages/Python/lldbsuite/test/functionalities/gdb_remote_client/TestRecognizeBreakpoint.py
packages/Python/lldbsuite/test/functionalities/gdb_remote_client/gdbclientutils.py
packages/Python/lldbsuite/test/functionalities/gdb_remote_client/operating_system_2.py
source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp
source/Target/Process.cpp
Index: source/Target/Process.cpp
===================================================================
--- source/Target/Process.cpp
+++ source/Target/Process.cpp
@@ -3033,6 +3033,13 @@
if (!m_os_up)
LoadOperatingSystemPlugin(false);
+
+ // Somebody might have gotten threads before now, but we need to force the
+ // update after we've loaded the OperatingSystem plugin or it won't get a
+ // chance to process the threads.
+ m_thread_list.Clear();
+ UpdateThreadListIfNeeded();
+
// Figure out which one is the executable, and set that in our target:
const ModuleList &target_modules = GetTarget().GetImages();
std::lock_guard<std::recursive_mutex> guard(target_modules.GetMutex());
Index: source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp
===================================================================
--- source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp
+++ source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp
@@ -2426,6 +2426,15 @@
// Scope for the lock
{
+ // Check to see if SetThreadStopInfo() filled in m_thread_ids?
+ if (m_thread_ids.empty()) {
+ // No, we need to fetch the thread list manually
+ UpdateThreadIDList();
+ }
+ // We might set some stop info's so make sure the thread list is up to
+ // date before we do that or we might overwrite what was computed here.
+ UpdateThreadListIfNeeded();
+
// Lock the thread stack while we access it
std::lock_guard<std::recursive_mutex> guard(m_last_stop_packet_mutex);
// Get the number of stop packets on the stack
@@ -2440,13 +2449,7 @@
// Clear the thread stop stack
m_stop_packet_stack.clear();
}
-
- // Check to see if SetThreadStopInfo() filled in m_thread_ids?
- if (m_thread_ids.empty()) {
- // No, we need to fetch the thread list manually
- UpdateThreadIDList();
- }
-
+
// If we have queried for a default thread id
if (m_initial_tid != LLDB_INVALID_THREAD_ID) {
m_thread_list.SetSelectedThreadByID(m_initial_tid);
Index: packages/Python/lldbsuite/test/functionalities/gdb_remote_client/operating_system_2.py
===================================================================
--- packages/Python/lldbsuite/test/functionalities/gdb_remote_client/operating_system_2.py
+++ packages/Python/lldbsuite/test/functionalities/gdb_remote_client/operating_system_2.py
@@ -0,0 +1,62 @@
+import lldb
+import struct
+
+
+class OperatingSystemPlugIn(object):
+ """Class that provides data for an instance of a LLDB 'OperatingSystemPython' plug-in class
+ This version stops once with threads 0x111 and 0x222, then stops a second time with threads
+ 0x111 and 0x333."""
+
+ def __init__(self, process):
+ '''Initialization needs a valid.SBProcess object.
+
+ This plug-in will get created after a live process is valid and has stopped for the first time.
+ '''
+ self.process = None
+ self.registers = None
+ self.threads = None
+ self.times_called = 0
+ if isinstance(process, lldb.SBProcess) and process.IsValid():
+ self.process = process
+ self.threads = None # Will be an dictionary containing info for each thread
+
+ def get_target(self):
+ return self.process.target
+
+ def get_thread_info(self):
+ self.times_called += 1
+
+ if self.times_called == 1:
+ self.threads = [{
+ 'tid': 0x111,
+ 'name': 'one',
+ 'queue': 'queue1',
+ 'state': 'stopped',
+ 'stop_reason': 'none',
+ 'core': 1
+ }, {
+ 'tid': 0x222,
+ 'name': 'two',
+ 'queue': 'queue2',
+ 'state': 'stopped',
+ 'stop_reason': 'none',
+ 'core': 0
+ }]
+ else:
+ self.threads = [{
+ 'tid': 0x111,
+ 'name': 'one',
+ 'queue': 'queue1',
+ 'state': 'stopped',
+ 'stop_reason': 'none',
+ 'core': 1
+ }, {
+ 'tid': 0x333,
+ 'name': 'three',
+ 'queue': 'queue3',
+ 'state': 'stopped',
+ 'stop_reason': 'none',
+ 'core': 0
+ }]
+ return self.threads
+
Index: packages/Python/lldbsuite/test/functionalities/gdb_remote_client/gdbclientutils.py
===================================================================
--- packages/Python/lldbsuite/test/functionalities/gdb_remote_client/gdbclientutils.py
+++ packages/Python/lldbsuite/test/functionalities/gdb_remote_client/gdbclientutils.py
@@ -103,6 +103,8 @@
return self.interrupt()
if packet == "c":
return self.cont()
+ if packet.startswith("vCont;c"):
+ return self.vCont(packet)
if packet[0] == "g":
return self.readRegisters()
if packet[0] == "G":
@@ -168,6 +170,9 @@
def cont(self):
raise self.UnexpectedPacketException()
+ def vCont(self, packet):
+ raise self.UnexpectedPacketException()
+
def readRegisters(self):
return "00000000" * self.registerCount
Index: packages/Python/lldbsuite/test/functionalities/gdb_remote_client/TestRecognizeBreakpoint.py
===================================================================
--- packages/Python/lldbsuite/test/functionalities/gdb_remote_client/TestRecognizeBreakpoint.py
+++ packages/Python/lldbsuite/test/functionalities/gdb_remote_client/TestRecognizeBreakpoint.py
@@ -0,0 +1,139 @@
+from __future__ import print_function
+import lldb
+from lldbsuite.test.lldbtest import *
+from lldbsuite.test.decorators import *
+from gdbclientutils import *
+
+
+class TestRecognizeBreakpoint(GDBRemoteTestBase):
+ """ This tests the case where the gdb-remote server doesn't support any
+ of the thread-info packets, and just tells which thread got the stop
+ signal with:
+ T05thread:01;
+ There was a bug in lldb that we would set the stop reason from this
+ packet too early - before we had updated the thread list. So when we
+ later updated the thread list, we would throw away this info. Normally
+ we would be able to reconstruct it from the thread info, but not if the
+ stub doesn't support it """
+
+ def test(self):
+ class MyResponder(MockGDBServerResponder):
+ def __init__(self):
+ MockGDBServerResponder.__init__(self)
+ self.thread_info_count = 0
+ self.after_cont = False
+ self.current_thread = 0
+
+ def cont(self):
+ # Simulate process stopping due to a breakpoint:
+ self.after_cont = True
+ return "T05thread:01;"
+
+ def vCont(self, packet):
+ self.after_cont = True
+ return "T05thread:01;"
+
+ def haltReason(self):
+ return "T02thread:01;"
+
+ def threadStopInfo(self, num):
+ return ""
+
+ def QThreadSuffixSupported(self):
+ return ""
+
+ def QListThreadsInStopReply(self):
+ return ""
+
+ def setBreakpoint(self, packet):
+ return "OK"
+
+ def qfThreadInfo(self):
+ return "m1"
+
+ def qsThreadInfo(self):
+ if (self.thread_info_count % 2) == 0:
+ str = "m2"
+ else:
+ str = "l"
+ self.thread_info_count += 1
+ return str
+
+ def readRegisters(self):
+ if self.after_cont and self.current_thread == 1:
+ return "c01e990080ffffff"
+ else:
+ return "badcfe10325476980"
+
+ def readRegister(self, regno):
+ return ""
+
+ def qXferRead(self, obj, annex, offset, length):
+ if annex == "target.xml":
+ return """<?xml version="1.0"?>
+ <target version="1.0">
+ <architecture>i386:x86-64</architecture>
+ <feature name="org.gnu.gdb.i386.core">
+ <reg name="rip" bitsize="64" regnum="0" type="code_ptr" group="general"/>
+ </feature>
+ </target>""", False
+ else:
+ return None, False
+
+ def selectThread(self, op, thread):
+ if op != 'g':
+ return ''
+
+ self.current_thread = thread
+ return "OK"
+
+ def other (self, packet):
+ if packet == "vCont?":
+ return "vCont;c;C;s;S"
+ return ''
+
+ python_os_plugin_path = os.path.join(self.getSourceDir(),
+ 'operating_system_2.py')
+ command ="settings set target.process.python-os-plugin-path '{}'".format(
+ python_os_plugin_path)
+ self.runCmd(command)
+
+ self.server.responder = MyResponder()
+ target = self.dbg.CreateTarget("")
+ process = self.connect(target)
+
+ bkpt = target.BreakpointCreateByAddress(0xffffff8000991ec0)
+ self.assertEqual(bkpt.GetNumLocations(), 1, "Fake breakpoint was resolved.")
+
+ # Get the initial stop, and we should have two threads.
+ num_threads = len(process.threads)
+ self.assertEqual(num_threads, 2, "Got two threads")
+
+ thread_0 = process.threads[0]
+ self.assertEqual(thread_0.GetStopReason(), 1, "Thread_0 stopped for no reason")
+ self.assertEqual(thread_0.GetName(), "one", "Thread_0 is called one")
+
+ thread_1 = process.threads[1]
+ self.assertEqual(thread_1.GetStopReason(), 5, "Thread_0 stopped for SIGSTOP")
+ self.assertEqual(thread_1.GetName(), "two", "Thread_0 is called two")
+
+ # Now continue and we will fake hitting a breakpoint.
+ process.Continue()
+
+ self.assertEqual(process.GetState(),lldb.eStateStopped, "Process is stopped")
+ num_threads = len(process.threads)
+
+ num_threads = len(process.threads)
+ self.assertEqual(num_threads, 2, "Got two threads")
+
+ thread_0 = process.threads[0]
+ self.assertEqual(thread_0.GetStopReason(), 1, "Thread_0 stopped for no reason")
+ self.assertEqual(thread_0.GetName(), "one", "Thread_0 is called one")
+
+ thread_1 = process.threads[1]
+ self.assertEqual(thread_1.GetStopReason(), 3, "Thread_0 stopped for SIGTRAP")
+ self.assertEqual(thread_1.GetName(), "three", "Thread_0 is called three")
+
+ self.assertTrue(thread_1.IsValid(), "Thread_1 is valid")
+ self.assertEqual(thread_1.GetStopReason(), lldb.eStopReasonBreakpoint, "Stopped at breakpoint")
+
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