rr-debugger / rr-debugger/rr

Scratch memory isn't reentrant with inout params

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#284 1 comment 0 reactions 0 assignees View on GitHub

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Dominant language
C++
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Forks
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Merged PRs (30d)
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Description

For example

  • enter an _un_buffered may-block syscall like read()
  • fudge a pointer into scratch memory for the outparam buf argument to read
  • read() is interrupted by a signal
  • the signal handler enters another may-block syscall, say recv()
  • try to set up scratch pointers

Boom.

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First steps

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  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start by tracing scratch-memory setup for inout parameters around the reported read() and recv() may-block syscall sequence, including interruption by a signal handler. Reproduce the nested syscall case and inspect how scratch pointers are allocated and restored; done means the sequence no longer corrupts or reuses scratch memory incorrectly, with regression coverage for reentrancy.

Written by the indexing model from the issue text.

Assessment

Tech stack
cpp, linux
Domain
devtools, operating-systems
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Needs clarification
Newbie friendliness
35/100

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