Threads are blocked in malloc and free, virtual size
- by Albert Wang
Hi, I'm running a 64-bit multi-threaded program on the windows server 2003 server (X64), It run into a case that some of the threads seem to be blocked in the malloc or free function forever. The stack trace is like follows:
ntdll.dll!NtWaitForSingleObject() + 0xa bytes
ntdll.dll!RtlpWaitOnCriticalSection() - 0x1aa bytes
ntdll.dll!RtlEnterCriticalSection() + 0xb040 bytes
ntdll.dll!RtlpDebugPageHeapAllocate() + 0x2f6 bytes
ntdll.dll!RtlDebugAllocateHeap() + 0x40 bytes
ntdll.dll!RtlAllocateHeapSlowly() + 0x5e898 bytes
ntdll.dll!RtlAllocateHeap() - 0x1711a bytes
MyProg.exe!malloc(unsigned __int64 size=0) Line 168 C
MyProg.exe!operator new(unsigned __int64 size=1) Line 59 + 0x5 bytes C++
ntdll.dll!NtWaitForSingleObject()
ntdll.dll!RtlpWaitOnCriticalSection()
ntdll.dll!RtlEnterCriticalSection()
ntdll.dll!RtlpDebugPageHeapFree()
ntdll.dll!RtlDebugFreeHeap()
ntdll.dll!RtlFreeHeapSlowly()
ntdll.dll!RtlFreeHeap()
MyProg.exe!free(void * pBlock=0x000000007e8e4fe0) C
BTW, the param values passed to the new operator is not correct here maybe due to optimization.
Also, at the same time, I found in the process Explorer, the virtual size of this program is 10GB, but the private bytes and working set is very small (<2GB). We did have some threads using virtualalloc but in a way that commit the memory in the call, and these threads are not blocked.
m_pBuf = VirtualAlloc(NULL, m_size, MEM_COMMIT, PAGE_READWRITE);
......
VirtualFree(m_pBuf, 0, MEM_RELEASE);
This looks strange to me, seems a lot of virtual space is reserved but not committed, and malloc/free is blocked by lock. I'm guessing if there's any corruptions in the memory/object, so plan to turn on gflag with pageheap to troubleshoot this.
Does anyone has similar experience on this before? Could you share with me so I may get more hints?
Thanks a lot!
