Unable to Read ClrThreadStaticField Values on Linux

[meriffa]

Hi,

I am trying to get the value of a ClrThreadStaticField field in .NET Core on Linux using ClrMD. Here are the application details:

Target application:

private static readonly ThreadLocal<string> threadLocal = new();

ClrMD application:

foreach (var field in clrObject.Type.ThreadStaticFields)
  DisplayFieldValues(runtime, field);
...
private void DisplayFieldValues(ClrRuntime runtime, ClrThreadStaticField field)
{
  foreach (var thread in runtime.Threads)
      if (field.IsObjectReference)
      {
        var fieldInitialized = field.IsInitialized(thread);
        var fieldAddress = field.GetAddress(thread);
        var fieldValue = field.ReadObject(thread);
      }
}

The ClrMD application uses a full core dump of the Target application created using createdump -f.

In my case ClrThreadStaticField.GetAddress() returns 0 for all threads. As a result ClrThreadStaticField.ReadObject() returns null object (ClrObject.IsNull) for all threads as well.

Everything in LLDB using SOS works as expected:

(lldb) dumpobj 00007eec268c7468
Name:        System.Threading.ThreadLocal`1[[System.String, System.Private.CoreLib]]
...
Fields:
              MT    Field   Offset                 Type VT     Attr            Value Name
....
0000000000000000  4000d1e       10              SZARRAY  0 TLstatic  ts_slotArray
    >> Thread:Value 50e0:00007eec268c7aa0 50e2:00007eec268cb868 <<
00007f2c3d8373b0  4000d1f       18 ...Private.CoreLib]]  0 TLstatic  ts_finalizationHelper
    >> Thread:Value 50e0:00007eec268c7ac0 50e2:00007eec268cb888 <<

Here are the environment details:

• OS: Debian 12, x64, Linux VM-DEV 6.1.0-27-amd64 Add overloads to the GetValue() methods of ClrField classes that allo… #1 SMP PREEMPT_DYNAMIC Debian 6.1.115-1 (2024-11-01) x86_64 GNU/Linux
• .NET: Microsoft.NETCore.App 9.0.0 [/usr/share/dotnet/shared/Microsoft.NETCore.App]
• ClrMD:

Is there anything that I am missing?

Thanks,

Marian.

[wnayes]

This could be related to #1313. I am finding that I cannot read a .NET 10 static field, an am also running on Linux, though I do not know if the issue is specific to Linux or not.