#15211: KDL in MultiLocker::ReadLock()
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Reporter: 3dEyes | Owner: waddlesplash
Type: bug | Status: assigned
Priority: normal | Milestone: Unscheduled
Component: System/Kernel | Version: R1/Development
Resolution: | Keywords:
Blocked By: | Blocking:
Has a Patch: 0 | Platform: All
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Comment (by tqh):
I don't think the current multilocker looks safe. The check if it is
locked and the action afterward is not done in any kind of transaction. No
lock, no mem barrier. So when the action is done it might have already
changed state by another thread.
If it is intentional that several threads see it as unlocked and then
start locking it should be documented.
I also see problems if several threads would call destruction.
I don't think these kind of changes should be done this lightly, and I
would like to see some tests to guarantee that it has been proven to work
before commited.
You should be able to test this with mock threads and sleeps right after
each lock check return otherwise you will have subtle errors like this
where lock thread will be updated as soon as sem is relaased as others
hang there.
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Ticket URL: <https://dev.haiku-os.org/ticket/15211#comment:15>
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