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https://issues.apache.org/jira/browse/TINKERPOP-3087?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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David Bennington updated TINKERPOP-3087:
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Attachment: tinkerpop-3087.diff
> Panic in gremlin-go driver responseHandler
> ------------------------------------------
>
> Key: TINKERPOP-3087
> URL: https://issues.apache.org/jira/browse/TINKERPOP-3087
> Project: TinkerPop
> Issue Type: Bug
> Components: go
> Affects Versions: 3.7.1
> Environment: Ubuntu 20.04, x86_64, AWS EC2 image. Think it's 2c2g,
> can't recall off the top of my head.
> Compiled _without_ CGO.
> Reporter: David Bennington
> Priority: Minor
> Attachments: tinkerpop-3087.diff, tinkerpop-3087.txt
>
>
> Ocasionally, I get the following panic in the gremlin-go driver:
>
> {noformat}
> 10:22:39.895 <successfully added a vertex to janusgraph>
> 10:22:44.487 panic: runtime error: invalid memory address or nil pointer
> dereference
> 10:22:44.487 [signal SIGSEGV: segmentation violation code=0x1 addr=0x78
> pc=0x11fdd16]
> 10:22:44.487
> 10:22:44.487 goroutine 275 [running]:
> 10:22:44.487
> github.com/apache/tinkerpop/gremlin-go/v3/driver.(*gremlinServerWSProtocol).responseHandler(0xc0006be6c0,
> 0xc0001dfc60, {{0x9, 0xf6, 0x33, 0x7f, 0x19, 0x16, 0x4e, 0xc9, ...}, ...})
> 10:22:44.487
> /go/pkg/mod/github.com/apache/tinkerpop/gremlin-go/[email protected]/driver/protocol.go:116
> +0x7d6
> 10:22:44.487
> github.com/apache/tinkerpop/gremlin-go/v3/driver.(*gremlinServerWSProtocol).readLoop(0xc0006be6c0,
> 0xc0001dfc60, 0xc0001dfca0)
> 10:22:44.487
> /go/pkg/mod/github.com/apache/tinkerpop/gremlin-go/[email protected]/driver/protocol.go:82
> +0x272
> 10:22:44.487 created by
> github.com/apache/tinkerpop/gremlin-go/v3/driver.newGremlinServerWSProtocol
> in goroutine 272
> 10:22:44.487
> /go/pkg/mod/github.com/apache/tinkerpop/gremlin-go/[email protected]/driver/protocol.go:197
> +0x23a{noformat}
> I can't reliably reproduce, it's never happened locally. It's occurred just
> after doing some work in the logs above, but it's also happened after a
> period of doing nothing.
>
> First glance looks like it's a nil being returned from the `resultSets`
> synchronizedMap, something getting in and removing it, which should only
> happen when the `channelResultSet` itself is closed? Seems like a race
> condition to me.
> I think the sensible way to handle this, if it is what I suspect (I've no
> proof yet), would be to
> * Store a reference to the ResultSet when first loading it in responseHandler
> * Make `channelResultSet` discard modifications after close OR
> * responseHandler needs to aquire the `channelMutex` somehow for the
> duration of modifications (I think I prefer this, it's more obvious to what's
> happening)
> I did try and get the project tests to run, but it's been _years_ since I've
> had to use maven and I can't seem to find a good idiots guide to working with
> the project from a non java POV - I need to know how to build the docker
> images the tests require. If someone could help me get started I'd be more
> than happy to contribute a PR (although given the nature, a reliable test may
> be hard to write).
> As it stands, I'm probably going to modify my fork and mod replace, see if a
> fix would actually work in my deployments.
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