rr-debugger / rr-debugger/rr

Assertion !syscall_bp_vm failed to hold during replay

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Description

During singlestepping through & across spidermonkey's compacting GC I ran into a !syscall_bp_vm crash. (See also #1745, same symptoms.) Logs attached.

I'm pretty sure the crash happened almost exactly at midnight local time (we're at UTC+1 now) but I didn't realize that until this morning, so I didn't attempt to verify it at the time. But I made some noise about it on IRC at 00:01.

This is RR from a few weeks ago, Fedora 28, x86_64 with Xeons.

rr-backtrace.txt

Today I've been using rr intensively in the same setting without this incident at all, so it is definitely some kind of intermittent problem.

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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 reading the attached rr-backtrace.txt and comparing the symptoms with issue #1745. Investigate the intermittent !syscall_bp_vm assertion during SpiderMonkey compacting-GC single-stepping; done means identifying and fixing the replay failure and verifying that this scenario no longer crashes.

Written by the indexing model from the issue text.

Assessment

Tech stack
cpp, linux
Domain
devtools, operating-systems
Issue type
Bug
Difficulty
5/5
Estimated time
Over a week
Activity status
Stale
Clarity
Needs clarification
Newbie friendliness
20/100

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