Our application on startup creates a number of UnityWebRequests to download some data. If we quit the application right after we've launched it, and the requests are still active, we seem to experience a crash. Looking at the crash dump and with Unity's symbols loaded, it seems to point at some issue related to the UnityWebRequestManager.
The exception states: "The thread tried to read from or write to a virtual address for which it does not have the appropriate access".
The assembly shown is the following:
00007FF6115694E0 lea rcx,[UnityWebRequestManager::m_ActiveDownloadScriptHandlerLock (07FF61190C500h)]
00007FF6115694E7 jmp Mutex::~Mutex (07FF610B909B0h)
00007FF6115694EC int 3
00007FF6115694ED int 3
00007FF6115694EE int 3
00007FF6115694EF int 3
00007FF6115694F0 sub rsp,28h
00007FF6115694F4 mov rax,qword ptr [UnityWebRequestManager::m_Requests (07FF61190C4A8h)]
00007FF6115694FB mov rdx,qword ptr [rax]
00007FF6115694FE mov qword ptr [rax],rax
00007FF611569501 mov rax,qword ptr [UnityWebRequestManager::m_Requests (07FF61190C4A8h)]
00007FF611569508 mov qword ptr [rax+8],rax
00007FF61156950C mov rcx,qword ptr [UnityWebRequestManager::m_Requests (07FF61190C4A8h)]
00007FF611569513 mov qword ptr [UnityWebRequestManager::m_Requests+8h (07FF61190C4B0h)],0
00007FF61156951E cmp rdx,rcx
00007FF611569521 je `memory_pool_impl<56>::get_pool'::`2'::`dynamic atexit destructor for 'pool''+45Fh (07FF61156954Fh)
00007FF611569523 mov qword ptr [rsp+20h],rbx
00007FF611569528 nop dword ptr [rax+rax]
00007FF611569530 mov rbx,qword ptr [rdx] <-------- LOCATION OF THE CRASH
00007FF611569533 mov rcx,rdx
00007FF611569536 call operator delete[] (07FF610CCD7F0h)
00007FF61156953B mov rcx,qword ptr [UnityWebRequestManager::m_Requests (07FF61190C4A8h)]
00007FF611569542 mov rdx,rbx
00007FF611569545 cmp rbx,rcx
00007FF611569548 jne `memory_pool_impl<56>::get_pool'::`2'::`dynamic atexit destructor for 'pool''+440h (07FF611569530h)
00007FF61156954A mov rbx,qword ptr [rsp+20h]
00007FF61156954F add rsp,28h
00007FF611569553 jmp operator delete[] (07FF610CCD7F0h)
00007FF611569558 int 3
00007FF611569559 int 3
00007FF61156955A int 3
00007FF61156955B int 3
00007FF61156955C int 3
00007FF61156955D int 3
00007FF61156955E int 3
00007FF61156955F int 3
00007FF611569560 sub rsp,28h
To try and fix the issue we've explicitly been trying to Abort all active UnityWebRequests on application quit, but this has not resolved the problem.
We're currently on Unity 5.6.5p1.
Any ideas what may cause this issue? Are UnityWebRequests supposed to gracefully handle application quits, or is there something we should do? Or am I misinterpreting the assembly shown?
↧