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classification
Title: Uninitialised variable in _PyObject_GenericSetAttrWithDict
Type: compile error Stage:
Components: Installation Versions:
process
Status: closed Resolution: out of date
Dependencies: Superseder:
Assigned To: Nosy List: Jim.Jewett, Mark.Shannon, benjamin.peterson
Priority: normal Keywords: patch

Created on 2012-03-09 10:04 by Mark.Shannon, last changed 2022-04-11 14:57 by admin. This issue is now closed.

Files
File name Uploaded Description Edit
uninitialised_descr.patch Mark.Shannon, 2012-03-09 10:04 review
Messages (3)
msg155221 - (view) Author: Mark Shannon (Mark.Shannon) * (Python committer) Date: 2012-03-09 10:04
I get the following compiler warning (rev 2a142141e5fd)
Its not strictly an error, but an unitialised variable in such an 
important function is dangerous.

Objects/object.c: In function ‘_PyObject_GenericSetAttrWithDict’:
Objects/object.c:1144: warning: ‘descr’ may be used uninitialised in this function

Patch attached
msg155257 - (view) Author: Benjamin Peterson (benjamin.peterson) * (Python committer) Date: 2012-03-09 19:15
Fixed in differently in 46e600fa8d05 Thanks anyway.
msg155259 - (view) Author: Jim Jewett (Jim.Jewett) * (Python triager) Date: 2012-03-09 19:23
So the risk is that descr may be given garbage memory that just happens to look like an object with 1 reference, so that it really does a decref and tries to re-deallocate whatever was there before.

I would rather see the change at the top of the function; just initialize descr to NULL when it is declared, and let the compiler figure out that it can skip the zeroing on some (most) paths.
History
Date User Action Args
2022-04-11 14:57:27adminsetgithub: 58447
2012-03-09 19:23:13Jim.Jewettsetnosy: + Jim.Jewett
messages: + msg155259
2012-03-09 19:15:50benjamin.petersonsetstatus: open -> closed
resolution: out of date
messages: + msg155257
2012-03-09 17:18:56pitrousetnosy: + benjamin.peterson
2012-03-09 10:04:22Mark.Shannoncreate