wallace created this revision.
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There's a bug caused when a process is relaunched: the target, which
doesn't change, keeps the Trace object from the previous process, which
is already defunct, and causes segmentation faults when it's attempted
to be used.
A fix is to clean up the Trace object when the target is disposing of
the previous process during relaunches.
A way to reproduce this:
lldb a.out
b main
r
process trace start
c
r
process trace start
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D122176
Files:
lldb/source/Target/Target.cpp
lldb/test/API/commands/trace/TestTraceStartStop.py
Index: lldb/test/API/commands/trace/TestTraceStartStop.py
===================================================================
--- lldb/test/API/commands/trace/TestTraceStartStop.py
+++ lldb/test/API/commands/trace/TestTraceStartStop.py
@@ -166,3 +166,13 @@
self.expect("thread trace stop", error=True,
substrs=["error: Process must be launched"])
+
+ # We should be able to trace the program if we relaunch it
+ self.expect("r")
+ self.expect("thread trace start")
+ # We can reconstruct the single instruction executed in the first line
+ self.expect("n")
+ self.expect("thread trace dump instructions -f",
+ patterns=[f'''thread #1: tid = .*
+ a.out`main \+ 4 at main.cpp:2
+ \[ 0\] {ADDRESS_REGEX} movl'''])
Index: lldb/source/Target/Target.cpp
===================================================================
--- lldb/source/Target/Target.cpp
+++ lldb/source/Target/Target.cpp
@@ -185,6 +185,8 @@
void Target::DeleteCurrentProcess() {
if (m_process_sp) {
+ // We dispose any active tracing sessions on the current process
+ m_trace_sp.reset();
m_section_load_history.Clear();
if (m_process_sp->IsAlive())
m_process_sp->Destroy(false);
Index: lldb/test/API/commands/trace/TestTraceStartStop.py
===================================================================
--- lldb/test/API/commands/trace/TestTraceStartStop.py
+++ lldb/test/API/commands/trace/TestTraceStartStop.py
@@ -166,3 +166,13 @@
self.expect("thread trace stop", error=True,
substrs=["error: Process must be launched"])
+
+ # We should be able to trace the program if we relaunch it
+ self.expect("r")
+ self.expect("thread trace start")
+ # We can reconstruct the single instruction executed in the first line
+ self.expect("n")
+ self.expect("thread trace dump instructions -f",
+ patterns=[f'''thread #1: tid = .*
+ a.out`main \+ 4 at main.cpp:2
+ \[ 0\] {ADDRESS_REGEX} movl'''])
Index: lldb/source/Target/Target.cpp
===================================================================
--- lldb/source/Target/Target.cpp
+++ lldb/source/Target/Target.cpp
@@ -185,6 +185,8 @@
void Target::DeleteCurrentProcess() {
if (m_process_sp) {
+ // We dispose any active tracing sessions on the current process
+ m_trace_sp.reset();
m_section_load_history.Clear();
if (m_process_sp->IsAlive())
m_process_sp->Destroy(false);
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