[lldb-dev] Problems with core load on Linux and proposed solution

Eugene Birukov via lldb-dev lldb-dev at lists.llvm.org
Thu Jan 21 10:45:30 PST 2016

LLDB 3.8 has much better support for core load on Linux than 3.7 - thanks a lot! But there are still two problems.
1. The thread ID are lost and there is FIXME in the code2. If core dump is obtained from live process (i.e. gdb attach, gcore, detach) then there is no thread that has any reason to stop. LLDB hangs forever on such a core.
Here is the fix that works for me for both problems.
diff --git a/include/lldb/Target/Process.h

index 6bb7a3d..915ca15 100644

--- a/include/lldb/Target/Process.h

+++ b/include/lldb/Target/Process.h

@@ -3401,6 +3401,7 @@ protected:

std::map<lldb::addr_t,lldb::addr_t> m_resolved_indirect_addresses;

     bool m_destroy_in_process;

     bool m_can_interpret_function_calls; //
Some targets, e.g the OSX kernel, don't support the ability to modify the

+    bool m_load_core; // True if we are looking at a core dump, not at a running program

m_warnings_issued;  // A set of object pointers which have already had
warnings printed


     enum {

diff --git a/source/Plugins/Process/elf-core/ProcessElfCore.cpp

index 5b5d98a..fa057f1 100644

--- a/source/Plugins/Process/elf-core/ProcessElfCore.cpp

+++ b/source/Plugins/Process/elf-core/ProcessElfCore.cpp

@@ -559,11 +559,10 @@ ProcessElfCore::ParseThreadContextsFromNoteSegment(const
elf::ELFProgramHeader *

have_prstatus = true;

prstatus.Parse(note_data, arch);

thread_data->signo = prstatus.pr_cursig;

 thread_data->tid = prstatus.pr_pid;

header_size = ELFLinuxPrStatus::GetSize(arch);

len = note_data.GetByteSize() - header_size;

thread_data->gpregset = DataExtractor(note_data, header_size, len);

// FIXME: Obtain actual tid on Linux

thread_data->tid = m_thread_data.size();



thread_data->fpregset = note_data;

diff --git a/source/Target/Process.cpp

index e4fe419..489b307 100644

--- a/source/Target/Process.cpp

+++ b/source/Target/Process.cpp

@@ -767,6 +767,7 @@ Process::Process(lldb::TargetSP target_sp,
Listener &listener, const UnixSignals

     m_last_broadcast_state (eStateInvalid),

     m_destroy_in_process (false),


+    m_load_core(false),

     m_warnings_issued (),



@@ -3088,6 +3089,7 @@ Process::LoadCore ()

         // We
successfully loaded a core file, now pretend we stopped so we can

         // show all of
the threads in the core file and explore the crashed

         // state.

+        m_load_core = true;



         // Wait indefinitely
for a stopped event since we just posted one above...

@@ -3975,6 +3977,11 @@ Process::ShouldBroadcastEvent (Event


if (!was_restarted)

should_resume = m_thread_list.ShouldStop (event_ptr) == false;


// ShouldStop() above has some side effects besides calculating return value,

// so we better not skip it. But if we are loading core we should not resume.

if (m_load_core)

should_resume = false;


if (was_restarted || should_resume || m_resume_requested)

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