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Re^2: panic: COND_DESTROY(6)

by menth0l (Monk)
on Feb 01, 2012 at 09:02 UTC ( #951153=note: print w/replies, xml ) Need Help??


in reply to Re: panic: COND_DESTROY(6)
in thread panic: COND_DESTROY(6)

Maybe you're right. I added a tons of logging just next to each lock occurrence to see at which point my app fails. I found that each time it was crashing near calling this function:
sub UnshareHash { my $reference = shift; lock $reference if is_shared($reference); given (ref $reference) { when ('HASH') { return { map UnshareHash($_), %{$reference} } } when ('ARRAY') { return [ map UnshareHash($_), @{$reference} ] } when ('REF') { return \UnshareHash($$reference) } default { return $reference } } }
I have a configuration object shared between threads which sometimes need to clone/unshare some part of it using the function above. I've changed the function to lock only the top-level structure:
sub UnshareHash { my $reference = shift; my $deep = shift; lock $reference if is_shared($reference) and not $deep; given (ref $reference) { when ('HASH') { return { map UnshareHash($_, 1), %{$reference} } } when ('ARRAY') { return [ map UnshareHash($_, 1), @{$reference} ] } when ('REF') { return \UnshareHash($$reference, 1) } default { return $reference } } }
For now it looks promising: my app runs for about 40 straight hours now. Before that crash happened after few hours at most, sometimes after few minutes. But that may be just a coincidence, i'll have to wait some more time.

But if it happens to be true (i.e. UnshareHash() is the culprit) then i assume that recursive locking is the problem? That would be a bug in threads::shared, wouldn't it?

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[Corion]: Mr. Muskrat: I'm not sure if it really happens more often, but I don't exactly know either
[LanX]: yep
[LanX]: more often for some weeks now
[Corion]: I think I'll have to manually (as god) intervene with that node, as the simple reparenting didn't seem to fix the parent/child relationship of the nodes
[Corion]: I think I have an idea but I'll have to open a ticket with Pair.com on that - hopefully I get to that on the weekend
LanX imagines a burning thorn bush
[Mr. Muskrat]: Thank you!
[Mr. Muskrat]: Oh that is odd. I got the message that it was reparented but yeah, it didn't actually do it. lol
[Corion]: LanX: No, Co-Rion appears as Monkey God :-)
[Corion]: Mr. Muskrat: Yeah, that message is automatic when the "normal" reparenting is done, but I think some rows that make up the node were not added to the DB properly

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