8000 [3.8] bpo-39847: EnterNonRecursiveMutex() uses GetTickCount64() (GH-18780) by miss-islington · Pull Request #18945 · python/cpython · GitHub
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[3.8] bpo-39847: EnterNonRecursiveMutex() uses GetTickCount64() (GH-18780) #18945

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Merged
merged 1 commit into from
Mar 11, 2020
Merged

[3.8] bpo-39847: EnterNonRecursiveMutex() uses GetTickCount64() (GH-18780) #18945

merged 1 commit into from
Mar 11, 2020

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miss-islington
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@miss-islington miss-islington commented Mar 11, 2020 •
edited by bedevere-bot
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The 32-bit (49-day) TickCount relied on in EnterNonRecursiveMutex can overflow
in the gap between the 'target' time and the 'now' time WaitForSingleObjectEx
returns, causing the loop to think it needs to wait another 49 days. This is
most likely to happen when the machine is hibernated during
WaitForSingleObjectEx.

This makes acquiring a lock/event/etc from the _thread or threading module
appear to never timeout.

Replace with GetTickCount64 - this is OK now Python no longer supports XP which
lacks it, and is in use for time.monotonic().

Co-authored-by: And Clover and.clover@bromium.com
(cherry picked from commit 64838ce)

Co-authored-by: bobince and+github@doxdesk.com

https://bugs.python.org/issue39847

@bobince @miss-islington
bpo-39847: EnterNonRecursiveMutex() uses GetTickCount64() (pythonGH-1…
2a1a018 
…8780)

The 32-bit (49-day) TickCount relied on in EnterNonRecursiveMutex can overflow
in the gap between the 'target' time and the 'now' time WaitForSingleObjectEx
returns, causing the loop to think it needs to wait another 49 days. This is
most likely to happen when the machine is hibernated during
WaitForSingleObjectEx.

This makes acquiring a lock/event/etc from the _thread or threading module
appear to never timeout.

Replace with GetTickCount64 - this is OK now Python no longer supports XP which
lacks it, and is in use for time.monotonic().

Co-authored-by: And Clover <and.clover@bromium.com>
(cherry picked from commit 64838ce)

Co-authored-by: bobince <and+github@doxdesk.com>
@bedevere-bot bedevere-bot mentioned this pull request Mar 11, 2020
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vstinner
vstinner approved these changes Mar 11, 2020
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LGTM, good bot.

@miss-islington
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@bobince and @vstinner: Status check is done, and it's a success ✅ .

@miss-islington miss-islington merged commit 60b1b5a into python:3.8 Mar 11, 2020
@miss-islington miss-islington deleted the backport-64838ce-3.8 branch March 11, 2020 23:57
@miss-islington
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@bobince and @vstinner: Status check is done, and it's a success ✅ .

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@bobince and @vstinner: Status check is done, and it's a success ✅ .

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