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[3.7] bpo-9263: _PyObject_Dump() detects freed memory (GH-10061) #10662

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merged 2 commits into from
Nov 22, 2018
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[3.7] bpo-9263: _PyObject_Dump() detects freed memory (GH-10061) #10662

merged 2 commits into from
Nov 22, 2018

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@vstinner vstinner commented Nov 22, 2018 •
edited by bedevere-bot
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@vstinner
bpo-9263: _PyObject_Dump() detects freed memory (GH-10061)
a4d6ba8 
_PyObject_Dump() now uses an heuristic to check if the object memory
has been freed: log "<freed object>" in that case.

The heuristic rely on the debug hooks on Python memory allocators
which fills the memory with DEADBYTE (0xDB) when memory is
deallocated. Use PYTHONMALLOC=debug to always enable these debug
hooks.

(cherry picked from commit 82af0b6)
@vstinner
bpo-9263: Fix _PyObject_Dump() for freed object (#10661)
5f66a51 
If _PyObject_Dump() detects that the object is freed, don't try to
dump it (exit immediately).

Enhance also _PyObject_IsFreed(): it now detects if the pointer
itself looks like freed memory.

(cherry picked from commit 2cf5d32)
@vstinner vstinner merged commit 95036ea into python:3.7 Nov 22, 2018
@vstinner vstinner deleted the object_dump37 branch November 22, 2018 16:15
@miss-islington
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Thanks @vstinner for the PR 🌮🎉.. I'm working now to backport this PR to: 3.6.
🐍🍒⛏🤖

@miss-islington
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Sorry, @vstinner, I could not cleanly backport this to 3.6 due to a conflict.
Please backport using cherry_picker on command line.
cherry_picker 95036ea25d47f0081bda2ba96ea327f3375cb6a4 3.6

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GH-10663 is a backport of this pull request to the 3.6 branch.

vstinner added a commit that referenced this pull request Nov 22, 2018
@vstinner
bpo-9263: _PyObject_Dump() detects freed memory (GH-10061) (GH-10662) (…
c9b3fc6 
…GH-10663)

* bpo-9263: _PyObject_Dump() detects freed memory (GH-10061)

_PyObject_Dump() now uses an heuristic to check if the object memory
has been freed: log "<freed object>" in that case.

The heuristic rely on the debug hooks on Python memory allocators
which fills the memory with DEADBYTE (0xDB) when memory is
deallocated. Use PYTHONMALLOC=debug to always enable these debug
hooks.

(cherry picked from commit 82af0b6)

* bpo-9263: Fix _PyObject_Dump() for freed object (#10661)

If _PyObject_Dump() detects that the object is freed, don't try to
dump it (exit immediately).

Enhance also _PyObject_IsFreed(): it now detects if the pointer
itself looks like freed memory.

(cherry picked from commit 2cf5d32)
(cherry picked from commit 95036ea)
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