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https://github.com/python/cpython/pull/7287#discussion_r192545213 #1

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merged 1 commit into from
Jun 3, 2018

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@roseman roseman merged commit 9a5b0e8 into roseman:tkinter_docs Jun 3, 2018
@native-api native-api deleted the roseman_1 branch June 6, 2018 11:05
roseman pushed a commit that referenced this pull request Oct 24, 2020
```
Direct leak of 8 byte(s) in 1 object(s) allocated from:
    #0 0x7f008bf19667 in __interceptor_malloc (/lib64/libasan.so.6+0xb0667)
    #1 0x7f007a0bee4a in subprocess_fork_exec /home/heimes/dev/python/cpython/Modules/_posixsubprocess.c:774
    #2 0xe0305b in cfunction_call Objects/methodobject.c:546
```

Signed-off-by: Christian Heimes <christian@python.org>
roseman pushed a commit that referenced this pull request Dec 4, 2020
* bpo-40791: Make compare_digest more constant-time.

The existing volatile `left`/`right` pointers guarantee that the reads will all occur, but does not guarantee that they will be _used_. So a compiler can still short-circuit the loop, saving e.g. the overhead of doing the xors and especially the overhead of the data dependency between `result` and the reads. That would change performance depending on where the first unequal byte occurs. This change removes that optimization.

(This is change #1 from https://bugs.python.org/issue40791 .)
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2 participants