Fix suboptimal lock release in (*handler).getChainInfo.
#733
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Also remove direct access to h.chainInfo. No race condition currently possible because `h.chainInfo` is never set to `nil` but, if it were, `getChainInfo` could sometimes unnecessarily return `nil`. Possible source of bugs in the future.
gnattishness
commented
Aug 4, 2020
| @@ -212,7 +214,7 @@ func (h *handler) getRand(ctx context.Context, round uint64) ([]byte, error) { | |||
| } | |||
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| // make sure we aren't going to ask for a round that doesn't exist yet. | |||
| if time.Unix(chain.TimeOfRound(h.chainInfo.Period, h.chainInfo.GenesisTime, round), 0).After(time.Now()) { | |||
| if time.Unix(chain.TimeOfRound(info.Period, info.GenesisTime, round), 0).After(time.Now()) { | |||
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Calling h.getChainInfo() here is perhaps neater, but requires unnecessary locking.
Passing as a parameter encodes/enforces the current assumption that getRand is only called after a call to h.getChainInfo()
willscott
approved these changes
Aug 4, 2020
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Possible source of bugs in the future but not currently a problem, as
h.chainInfois never set tonilbut fromnil.getChainInfocould sometimes unnecessarily returnnilifh.chainInfowere set tonilafter releasing theh.chainInfoLkread lock.Also remove direct, unsynchronized access to
h.chainInfoinh.getRand(). Similarly not a bug in the current usage, but could be a source of crashes ifh.chainInfois set tonil, orh.getRand()isn't called after a previous call toh.getChainInfo()