rr-debugger / rr-debugger/rr

dlclose() causes .so unloaded and does not reload it back on reverse-continue

Open
#3,846 3 comments 0 reactions 0 assignees View on GitHub

Nobody has claimed this yet.

Dominant language
C++
Stars
10.7k
Forks
662
Avg merge
2d 3h
Merged PRs (30d)
2

Description

In continuation of #3845.

For the trace of the following sequence:

  1. dlopen(X.so)
  2. debugged code
  3. dlclose(X.so)
  4. After dlclose()

Until 4. is reached 2. displays X.so in info shared. But if 4. is reached in trace replay, reverse-continue to 2. does not return back X.so to loaded modules.

The workaround to this is restart from the start or replay dlopen() again. Saved checkpoints also restore correct modules list.

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  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 reproducing the listed dlopen(), execution, dlclose(), and reverse-continue sequence in rr, then compare the info shared module list with a replay that reaches the same point forward. Trace how shared-library state changes across dlclose() and reverse replay; done means reverse-continue restores X.so without restarting or replaying dlopen().

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
Mostly clear
Newbie friendliness
45/100

Get new issues in your inbox

A short digest of beginner-friendly GitHub issues.