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test_bad_getattr crashes on APPX test #84638

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test_bad_getattr crashes on APPX test#84638
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zooba
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3.8 (EOL)end of life3.9 (EOL)end of lifeOS-windowstype-crashA hard crash of the interpreter, possibly with a core dump

Description

@zooba
zooba
opened on Apr 30, 2020
BPO 40458
Nosy @pfmoore, @vstinner, @tjguk, @ambv, @zware, @zooba, @miss-islington
PRs
  • bpo-40458: Increase reserved stack space to prevent overflow crash on Windows #19845
  • [3.8] bpo-40458: Increase reserved stack space to prevent overflow crash on Windows (GH-19845) #19941
    		•

    Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.

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    GitHub fields:

    assignee = 'https://github.com/zooba'
closed_at = <Date 2020-09-24.20:39:51.631>
created_at = <Date 2020-04-30.23:10:27.627>
labels = ['3.8', 'OS-windows', 'type-crash', '3.9']
title = 'test_bad_getattr crashes on APPX test'
updated_at = <Date 2020-09-24.20:39:51.631>
user = 'https://github.com/zooba'

    bugs.python.org fields:

    activity = <Date 2020-09-24.20:39:51.631>
actor = 'steve.dower'
assignee = 'steve.dower'
closed = True
closed_date = <Date 2020-09-24.20:39:51.631>
closer = 'steve.dower'
components = ['Windows']
creation = <Date 2020-04-30.23:10:27.627>
creator = 'steve.dower'
dependencies = []
files = []
hgrepos = []
issue_num = 40458
keywords = ['patch']
message_count = 8.0
messages = ['367803', '367880', '367881', '367888', '368060', '368185', '368186', '368189']
nosy_count = 7.0
nosy_names = ['paul.moore', 'vstinner', 'tim.golden', 'lukasz.langa', 'zach.ware', 'steve.dower', 'miss-islington']
pr_nums = ['19845', '19941']
priority = 'normal'
resolution = 'fixed'
stage = 'resolved'
status = 'closed'
superseder = None
type = 'crash'
url = 'https://bugs.python.org/issue40458'
versions = ['Python 3.8', 'Python 3.9']

    Activity

    1. zooba commented on Apr 30, 2020

      @zooba
      zooba
      on Apr 30, 2020
      MemberAuthor

      The Windows CI machines on Azure Pipelines run additional tests to check an "installed" layout and with the UWP entry point that's used for the Windows Store package.

      These tests have been failing intermittently (though regularly) with a stack overflow crash in the PyPickler tests.

      Example: https://dev.azure.com/Python/cpython/_build/results?buildId=62055&view=results

      test_attribute_name_interning (test.test_pickle.PyPicklerTests) ... ok
      File "D:\a\1\b\layout-appx-amd64\lib\test\pickletester.py", line 3085 in __getattr__
      File "D:\a\1\b\layout-appx-amd64\lib\test\pickletester.py", line 3085 in __getattr__
      File "D:\a\1\b\layout-appx-amd64\lib\test\pickletester.py", line 3085 in __getattr__
      File "D:\a\1\b\layout-appx-amd64\lib\test\pickletester.py", line 3085 in __getattr__
      ...

      I assume this is due to having more code on the start at the start, and so the recursion limit isn't low enough. But it might also be worth checking this particular case to see whether there is unnecessary data being kept on the stack (e.g. in local C variables).

      The crash occurs in both 3.8 and master, but not 3.7.

    2. zooba
      added
      3.8 (EOL)end of life
      3.9 (EOL)end of life
      OS-windows
      on Apr 30, 2020

    3. zooba commented on May 1, 2020

      @zooba
      zooba
      on May 1, 2020
      MemberAuthor

      Turns out the stack reservation was different, which is why it was crashing.

      As part of diagnosing it, I added the recursion count to faulthandler's output on Windows, but couldn't see if/where to do it for other platforms - Victor, any suggestions?

    4. zooba
      added
      type-crashA hard crash of the interpreter, possibly with a core dump
      on May 1, 2020

    5. zooba commented on May 1, 2020

      @zooba
      zooba
      on May 1, 2020
      MemberAuthor

      Also, it was really test_bad_getattr that was crashing.

    6. zooba
      changed the title [-]test_attribute_name_interning crashes on APPX test[/-] [+]test_bad_getattr crashes on APPX test[/+] on May 1, 2020
    7. zooba
      changed the title [-]test_attribute_name_interning crashes on APPX test[/-] [+]test_bad_getattr crashes on APPX test[/+] on May 1, 2020

    8. vstinner commented on May 1, 2020

      @vstinner
      vstinner
      on May 1, 2020
      Member

      Also, it was really test_bad_getattr that was crashing.

      Ah, an old friend. It seems like an issue with the maximum stack size. Here are my notes:
      https://pythondev.readthedocs.io/unstable_tests.html#unlimited-recursion

      Either reduce Python maximum stack depth, or increase the C stack size.

    9. zooba commented on May 4, 2020

      @zooba
      zooba
      on May 4, 2020
      MemberAuthor

      Yeah, I already got that part. If you check the PR, I added some better diagnostics to faulthandler for this case, but I don't see where I can add it for other platforms?

    10. zooba commented on May 5, 2020

      @zooba
      zooba
      on May 5, 2020
      MemberAuthor

      New changeset ac4bf42 by Steve Dower in branch 'master':
      bpo-40458: Increase reserved stack space to prevent overflow crash on Windows (GH-19845)
      ac4bf42

    11. zooba commented on May 5, 2020

      @zooba
      zooba
      on May 5, 2020
      MemberAuthor

      Merged without the improved diagnostics. I might add that later if I get time.

      Łukasz - this is a fairly trivial crash fix that'd be nice (and safe) to pull into 3.8.3, but not critical. Your call.

    12. zooba
      assigned
      zooba
      on May 5, 2020

    13. miss-islington commented on May 5, 2020

      @miss-islington
      miss-islington
      on May 5, 2020
      Contributor

      New changeset a6a116c by Miss Islington (bot) in branch '3.8':
      bpo-40458: Increase reserved stack space to prevent overflow crash on Windows (GH-19845)
      a6a116c

    14. zooba
      closed this as completedon Sep 24, 2020
    15. zooba
      closed this as completedon Sep 24, 2020
    16. ezio-melotti
      transferred this issue fromon Apr 10, 2022
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