[Numpy-discussion] numpy / ipython heisenbug crasher help?

[Zachary Pincus]

Hmm, I may have identified this by other means. See my next email...

Zach


On Aug 7, 2008, at 3:22 PM, Zachary Pincus wrote:

> Hello all,
>
> I have a bizarre bug that causes numpy to segfault, but:
>  - only when run under ipython
>  - only when numpy is imported *after* an other library (that does
> not import numpy)
>
> Here's what the code looks like.
> Crashes (only in ipython):
> import celltool.utility.pil_lite.Image as Image, numpy
> i = Image.open('untreated_2_logical.png')
> a = numpy.array(i)
>
> Does not crash:
> import numpy, celltool.utility.pil_lite.Image as Image
> i = Image.open('untreated_2_logical.png')
> a = numpy.array(i)
>
> The 'i' object exposes an __array_interface__, and is produced from my
> personal fork of the PIL.
>
> The crash is thusly reported:
> Exception Type:  EXC_BAD_ACCESS (SIGSEGV)
> Exception Codes: KERN_INVALID_ADDRESS at 0x000000000251f000
>
> 0   libSystem.B.dylib 0xffff0a13 __memcpy + 627
> 1   multiarray.so     0x022f7af8 _array_copy_into + 2840
> (arrayobject.c:1113)
> 2   multiarray.so     0x022f88af PyArray_FromArray + 495
> (arrayobject.c:8334)
> 3   multiarray.so     0x022ee314 PyArray_FromAny + 308 (arrayobject.c:
> 8814)
> 4   multiarray.so     0x022fb01c PyArray_CheckFromAny + 92
> (arrayobject.c:8995)
> 5   multiarray.so     0x022fb2e6 _array_fromobject + 310
> (multiarraymodule.c:5787)
> [And then the python stack frames]
>
> Can anyone suggest what a good next step in reducing this patently
> insane bug down to a more minimal test case is? I had this bug with
> numpy 1.1 as well as the current SVN head.
>
> Zach
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