CRASH when using dtltrace

Created by: jackery001

When using drltrace to record the call of adobe's program to cooltype, a crash occurs. After preliminary analysis, the reason for the crash is that the first parameter of the thread_get_mcontext function is NULL. I don't know why the parameter is empty.

os: win10 1809x64 17763.503 command line: drrun.exe -c drltrace.dll -only_to_lib CoolType -- "C:\Program Files (x86)\Adobe\Acrobat Reader DC\Reader\AcroRd32.exe" stack information: DrLTrace internal crash at PC 0x69bbb1e7. Please report this at http://dynamorio.org/issues. Program aborted. 0xc0000005 0x00000000 0x69bbb1e7 0x69bbb1e7 0x00000000 0x00000004 Base: 0x69b10000 Registers: eax=0x1ef1e914 ebx=0x1eef5040 ecx=0x000004e3 edx=0x00000000 esi=0x1ef1e914 edi=0x1eeff2fc esp=0x1ef1e904 ebp=0x00000003 eflags=0x00010 version 7.0.0, build 1 edx is the first parameter of the thread_get_mcontext.