[Lldb-commits] [lldb] 04202ab - [lldb][Process/FreeBSDKernelCore] Defer actual core loading to DoLoadCore() (#186626)

[via lldb-commits]

Author: Minsoo Choo
Date: 2026-04-10T17:49:29+09:00
New Revision: 04202abde35aaac906be29b250047c556a640f8c

URL: https://github.com/llvm/llvm-project/commit/04202abde35aaac906be29b250047c556a640f8c
DIFF: https://github.com/llvm/llvm-project/commit/04202abde35aaac906be29b250047c556a640f8c.diff

LOG: [lldb][Process/FreeBSDKernelCore] Defer actual core loading to DoLoadCore() (#186626)

`ProcessFreeBSDKernelCore` initializes `m_kvm` in class initialization,
thus invoking `kvm_open2()` only once. Although this approach is
effective, it violates the expected bahaviour of `DoLoadCore()`, loading
core file before the function is invoked. Later when I implement another
flavour of `ProcessFreeBSDKernelCore` inherited from `ProcessElfCore`,
ELF plugin will load core in `DoLoadCore()` while kvm plugin will do so
in the class initializer, causing discrepancy between the two classes.
Like the kvm/fvc precedent, the plugin variant (ELF and kvm) will be
chosen using vtable override, so if the behaviour differs like above, it
gets harder to add new features and debug the code. Thus, detecting and
loading core file in `ProcessFreeBSDKernelCore` should be handled
separately.

Signed-off-by: Minsoo Choo <minsoochoo0122 at proton.me>

Added: 
    

Modified: 
    lldb/source/Plugins/Process/FreeBSD-Kernel-Core/ProcessFreeBSDKernelCore.cpp
    lldb/source/Plugins/Process/FreeBSD-Kernel-Core/ProcessFreeBSDKernelCore.h

Removed: 
    


################################################################################
diff  --git a/lldb/source/Plugins/Process/FreeBSD-Kernel-Core/ProcessFreeBSDKernelCore.cpp b/lldb/source/Plugins/Process/FreeBSD-Kernel-Core/ProcessFreeBSDKernelCore.cpp
index d07e38f2783f0..4c07504672406 100644
--- a/lldb/source/Plugins/Process/FreeBSD-Kernel-Core/ProcessFreeBSDKernelCore.cpp
+++ b/lldb/source/Plugins/Process/FreeBSD-Kernel-Core/ProcessFreeBSDKernelCore.cpp
@@ -62,9 +62,8 @@ static PluginProperties &GetGlobalPluginProperties() {
 
 ProcessFreeBSDKernelCore::ProcessFreeBSDKernelCore(lldb::TargetSP target_sp,
                                                    ListenerSP listener_sp,
-                                                   kvm_t *kvm,
                                                    const FileSpec &core_file)
-    : PostMortemProcess(target_sp, listener_sp, core_file), m_kvm(kvm) {}
+    : PostMortemProcess(target_sp, listener_sp, core_file) {}
 
 ProcessFreeBSDKernelCore::~ProcessFreeBSDKernelCore() {
   m_thread_list.Clear();
@@ -84,9 +83,11 @@ lldb::ProcessSP ProcessFreeBSDKernelCore::CreateInstance(
     kvm_t *kvm =
         kvm_open2(executable->GetFileSpec().GetPath().c_str(),
                   crash_file->GetPath().c_str(), O_RDONLY, nullptr, nullptr);
-    if (kvm)
+    if (kvm) {
+      kvm_close(kvm);
       return std::make_shared<ProcessFreeBSDKernelCore>(target_sp, listener_sp,
-                                                        kvm, *crash_file);
+                                                        *crash_file);
+    }
   }
   return nullptr;
 }
@@ -118,7 +119,21 @@ bool ProcessFreeBSDKernelCore::CanDebug(lldb::TargetSP target_sp,
 }
 
 Status ProcessFreeBSDKernelCore::DoLoadCore() {
-  // The core is already loaded by CreateInstance().
+  ModuleSP executable = GetTarget().GetExecutableModule();
+  if (!executable)
+    return Status::FromErrorString(
+        "ProcessFreeBSDKernelCore: no executable module set on target");
+
+  m_kvm = kvm_open2(executable->GetFileSpec().GetPath().c_str(),
+                    GetCoreFile().GetPath().c_str(), O_RDWR, nullptr, nullptr);
+
+  if (!m_kvm)
+    return Status::FromErrorStringWithFormat(
+        "ProcessFreeBSDKernelCore: kvm_open2 failed for core '%s' "
+        "with kernel '%s'",
+        GetCoreFile().GetPath().c_str(),
+        executable->GetFileSpec().GetPath().c_str());
+
   SetKernelDisplacement();
 
   return Status();

diff  --git a/lldb/source/Plugins/Process/FreeBSD-Kernel-Core/ProcessFreeBSDKernelCore.h b/lldb/source/Plugins/Process/FreeBSD-Kernel-Core/ProcessFreeBSDKernelCore.h
index d82e55ea74bd9..77cb747fc95c1 100644
--- a/lldb/source/Plugins/Process/FreeBSD-Kernel-Core/ProcessFreeBSDKernelCore.h
+++ b/lldb/source/Plugins/Process/FreeBSD-Kernel-Core/ProcessFreeBSDKernelCore.h
@@ -17,7 +17,7 @@
 class ProcessFreeBSDKernelCore : public lldb_private::PostMortemProcess {
 public:
   ProcessFreeBSDKernelCore(lldb::TargetSP target_sp, lldb::ListenerSP listener,
-                           kvm_t *kvm, const lldb_private::FileSpec &core_file);
+                           const lldb_private::FileSpec &core_file);
 
   ~ProcessFreeBSDKernelCore();