clearerr called on NULL FILE* ?

[Chad Austin]

Hi all,

My first post to the list.  :)  I'm debugging one of our application 
crashes, and I thought maybe one of you has seen something similar 
before.  Our application is mostly Python, with some work being done in 
a native C++ module.  Anyway, I'm getting a memory access violation at 
the following stack:


CRASHING THREAD
EXCEPTION POINTERS: 0x0012e424
     ExceptionRecord: 0x0012e518
         ExceptionCode: 0xc0000005 EXCEPTION_ACCESS_VIOLATION
         ExceptionFlags: 0x00000000
         ExceptionAddress: 0x7c901010
         NumberParameters: 2
             ExceptionInformation[0]: 0x00000000
             ExceptionInformation[1]: 0x00000034
         ExceptionRecord: 0x00000000

THREAD ID: 10b0    frame count: 4
PYTHON23!0x000baa00 - PyFile_Type
PYTHON23!0x0003ac27 - PyFile_SetEncoding
   MSVCRT!0x00030a06 - clearerr
    ntdll!0x00001010 - RtlEnterCriticalSection


Here's my understanding:  something is getting called on a PyFileObject 
where f_fp is NULL, and clearerr in the multithreaded runtime tries to 
enter an invalid critical section.  It looks like PyFile_SetEncoding in 
the stack, but I can't figure out how in the Python source how 
SetEncoding calls clearerr.

Based on the timing of the crashes, I also think it might have something 
to do with log rollovers in RotatingFileHandler.

Has anyone run into something similar?  I don't expect anyone to spend a 
lot of time on this, but if there are any quick tips, they would be 
greatly appreciated...

We're using Python 2.3.5 and Visual C++ 6.

--
Chad Austin
http://imvu.com/technology