Description

xiaxinmeng

opened on Feb 15, 2023

Issue body actions

Crash report

In a function call, if one argument is split in two lines, CPython crashes. For example, we split the lambda expression, i.e., lamda_exp=lambda:1, in test2.py into two lines (See test1.py) . CPython reports a segmentation fault.

This crash just occurs on the latest main branch(e.g.commit a1f08f5, 8a2b7ee ). The older version of CPython(e.g. CPython 3.10.8, CPython 3.9.0 ) does not report any crash.

test1.py (Segmentation fault)

def foo(param, lambda_exp):
    pass

foo(param=0,
    lambda_exp=lambda:
    1)

test2.py (work well )

def foo(param, lambda_exp):
    pass

foo(param=0,
    lambda_exp=lambda:1)

Error messages

Segmentation Fault

Your environment

• CPython versions tested on: main branch from GitHub (commit a1f08f5)
• Operating system and architecture: Ubuntu 18.04

Linked PRs

• gh-101928: fix crash in compiler on multi-line lambda in function call #101933

Activity

1. xiaxinmeng

   added

   type-crashA hard crash of the interpreter, possibly with a core dumpA hard crash of the interpreter, possibly with a core dump

   on Feb 15, 2023
2. xiaxinmeng

   changed the title [-]Multi-line arguments in function call crashes CPython[/-] [+]Multi-line arguments in a function call crashes CPython[/+] on Feb 15, 2023
3. ronaldoussoren

   added

   interpreter-core(Objects, Python, Grammar, and Parser dirs)(Objects, Python, Grammar, and Parser dirs)

   on Feb 15, 2023
4. hauntsaninja commented on Feb 15, 2023

   

   hauntsaninja

   on Feb 15, 2023

   Contributor

   More actions

   Thanks for the report! I bisected this to #101633 cc @penguin-wwy @iritkatriel
5. kumaraditya303

   added

   3.12only security fixesonly security fixes

   release-blocker

   on Feb 15, 2023
6. ezio-melotti

   added this to Release and Deferred blockers 🚫on Feb 15, 2023
7. github-project-automation

   moved this to Todo in Release and Deferred blockers 🚫on Feb 15, 2023
8. iritkatriel commented on Feb 15, 2023

   

   iritkatriel

   on Feb 15, 2023

   Member

   More actions

   Thank you @hauntsaninja.

   I see the problem - we are now creating a basicblock with

   RETURN_CONST followed by NOP, and the redundant NOP is not being removed before propagate_line_numbers() uses BB_HAS_FALLTHROUGH on the block, which only looks at the last instruction to see if it exits the block.

   Possible fixes:

   1. (easiest) replace LOAD_CONST, RETURN_VALUE by NOP, RETURN_CONST (instead of RETURN_CONST, NOP).
   2. make sure the redundant NOP is removed before propagate_line_numbers is called

   I'll fix it tomorrow if nobody else will beat me to it.

   Reacted by penguin_wwy and Michael Droettboom
9. penguin-wwy commented on Feb 15, 2023

   

   penguin-wwy

   on Feb 15, 2023

   Contributor

   More actions

   Thank you @hauntsaninja.

   I see the problem - we are now creating a basicblock with

   RETURN_CONST followed by NOP, and the redundant NOP is not being removed before propagate_line_numbers() uses BB_HAS_FALLTHROUGH on the block, which only looks at the last instruction to see if it exits the block.

   Possible fixes:

   1. (easiest) replace LOAD_CONST, RETURN_VALUE by NOP, RETURN_CONST (instead of RETURN_CONST, NOP).
   
   2. make sure the redundant NOP is removed before propagate_line_numbers is called
   

   I'll fix it tomorrow if nobody else will beat me to it.

   @iritkatriel Thanks for the fix suggestion, I tried to fix it using the first method and it seems to have minimal impact and is effective.

   Reacted by Michael Droettboom
10. iritkatriel

    added a commit that references this issue on Feb 16, 2023

    gh-101928: fix crash in compiler on multi-line lambda in function call (

    df7ccf6
11. iritkatriel commented on Feb 16, 2023

    

    iritkatriel

    on Feb 16, 2023

    Member

    More actions

    Thanks for the report @xiaxinmeng, and for the fix @penguin-wwy .
12. iritkatriel

    closed this as completedon Feb 16, 2023
13. github-project-automation

    moved this from Todo to Done in Release and Deferred blockers 🚫on Feb 16, 2023

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