Explain.txt

EXCEPTION_ACCESS_VIOLATION_WRITE accessing 0x50

Thread 0 (crashed):
   0: server.dll + 0x1d7cbb
      eip: 0x78797cbb  esp: 0x00bbd8fc  ebp: 0x00bbd8fc  ebx: 0x00bbdac8
      esi: 0x22cbb780  edi: 0x00000000  eax: 0x78d3cb80  ecx: 0x00000000
      edx: 0x78797cb0  efl: 0x00210212  

__int64 __userpurge sub_101D7CB0@<edx:eax>(char a1@<efl>, int a2, float a3, float a4)

sub_101D7CB0      55                                      push    ebp
sub_101D7CB0+1    8B EC                                   mov     ebp, esp
sub_101D7CB0+3    8B 4D 08                                mov     ecx, [ebp+arg_0]
sub_101D7CB0+6    F3 0F 10 4D 0C                          movss   xmm1, [ebp+arg_4]
sub_101D7CB0+B  > 83 49 50 02                             or      dword ptr [ecx+50h], 2
sub_101D7CB0+F    F3 0F 10 11                             movss   xmm2, dword ptr [ecx]
sub_101D7CB0+13   0F 57 DB                                xorps   xmm3, xmm3

*(_DWORD *)(a2 + 80) |= 2u;

Crash happened due to "ecx" null pointer dereference.
Function prototype is unusual. There is no support for such register in DHook Detours,
so we are using own detour.
I was unable to find Linux accordance. There is no XRef.