508091 - BasicList needs to be mutation while iterating proof

Status: VERIFIED FIXED

(Tamarin Graveyard :: Garbage Collection (mmGC), defect)

Description

[Tommy Reilly]

When recieving abort messages GC's remove themselves from this list, it needs to handle this gracefully.

Comment 1

[Tommy Reilly]

Attachment: Makes list mutation while iterating work

Comment 2

[Edwin Smith]

Comment on attachment 392858 [details] [diff] [review]
Makes list mutation while iterating work


nits:
* if and while keywords should have a space between them and (
* Compact() needs a comment explaining how it works
* nice to have at least one comment per class saying what its for.
* needs self tests, probably

maybe problems:

* if an exception is thrown while a BasicListIterator is alive, then BasicList.iterationCount will not be decremented and will stay >0 forever.

If this can't happen, can we guard for it with assertions?  if not then at least a policy comment needs to be in there as a warning.

* must the BasicList mutator and iterator all be on the same thread?  if not then we need mutex code for IteratorAttach() and Detach().  and, probably other access paths.  if not, same story -- need safeguards and/or tests and/or comments to state the required contract.

most of our code is not thread aware but next(vmpi_spin_lock_t) got my attention.

Comment 3

[Tommy Reilly]

landed changeset:   2337:53b265ea55c9  w/ nits addressed.  

BasicList::next(vmpi_spin_lock_t) will probably go away, I'll create another bug to deal with the threading issues.