x/net/ipv4: SetICMPFilter panic in 1.9

[arthur-xie]

Suddenly, the tested(under OS X 10.11) functions (IPPing and TraceRoute diagnostics) fail to work any more.

The panic stack trace:

2017/12/03 14:42:22 [trace_route.go:259][E] 000000000001: Trace route panic: reflect: call of reflect.Value.Int on zero Value
2017/12/03 14:42:22 [trace_route.go:260][E] 000000000001: goroutine 71 [running]:
runtime/debug.Stack(0xc42023aff0, 0xc42003faa0, 0x2)
	/usr/local/Cellar/go/1.9/libexec/src/runtime/debug/stack.go:24 +0xa7
github.com/unosys/dm/unotr/agent.(*traceRoute).test.func1(0xc420158b40, 0xc42003ff18)
	/Users/arthur/WorkSpace/golang/src/github.com/unosys/dm/unotr/agent/trace_route.go:260 +0xcd
panic(0x462e620, 0xc420206120)
	/usr/local/Cellar/go/1.9/libexec/src/runtime/panic.go:491 +0x283
reflect.Value.Int(0x0, 0x0, 0x0, 0x46e4ff7)
	/usr/local/Cellar/go/1.9/libexec/src/reflect/value.go:908 +0x141
golang.org/x/net/internal/netreflect.socketOf(0x4a285c0, 0xc420418008, 0xc420418008, 0x4a285c0, 0xc420418008)
	/Users/arthur/WorkSpace/golang/src/golang.org/x/net/internal/netreflect/socket_posix.go:26 +0x196
golang.org/x/net/internal/netreflect.PacketSocketOf(0x4a28260, 0xc420418008, 0xc42003fc98, 0xc42003fca0, 0x4045b27)
	/Users/arthur/WorkSpace/golang/src/golang.org/x/net/internal/netreflect/socket.go:33 +0x7d
golang.org/x/net/ipv4.(*dgramOpt).SetICMPFilter(0xc4200801a0, 0xc42003fce0, 0xc420206060, 0x7)
	/Users/arthur/WorkSpace/golang/src/golang.org/x/net/ipv4/dgramopt_posix.go:248 +0x51
github.com/unosys/dm/unotr/agent.(*traceRoute).trace(0xc420414000, 0xc420158b40, 0x0, 0x0)
	/Users/arthur/WorkSpace/golang/src/github.com/unosys/dm/unotr/agent/trace_route.go:166 +0x1d0
github.com/unosys/dm/unotr/agent.(*traceRoute).test(0xc420414000, 0xc420158b40, 0x0, 0x0)
	/Users/arthur/WorkSpace/golang/src/github.com/unosys/dm/unotr/agent/trace_route.go:265 +0x7f
github.com/unosys/dm/unotr/agent.traceRouteHandler.func1(0xc420158b40, 0xc4203da660)
	/Users/arthur/WorkSpace/golang/src/github.com/unosys/dm/unotr/agent/trace_route.go:292 +0x96
created by github.com/unosys/dm/unotr/agent.traceRouteHandler
	/Users/arthur/WorkSpace/golang/src/github.com/unosys/dm/unotr/agent/trace_route.go:280 +0x67

Project code snippet:

var filter ipv4.ICMPFilter
filter.SetAll(true)
filter.Accept(ipv4.ICMPTypeTimeExceeded)
c.IPv4PacketConn().SetICMPFilter(&filter)

After switch back to 1.8.1, everything works fine.

[bradfitz]

What git revision of x/net are you using?

[arthur-xie]

Golang was installed through homebrew, I don't know how to check the git reversion. When try to upgrade, homebrew download it from https://homebrew.bintray.com/bottles/go-1.9.2.el_capitan.bottle.tar.gz. After this upgrade and updating GOROOT environment variable , the panic problem still exist.

[arthur-xie]

Sorry, I made a mistake. The x/net is not under the $GOROOT but $GOPATH/src/golang.org. The git info is:

$ git log -1
commit daba796358cd2742b75aae05761f1b898c9f6a5c
Author: Mikio Hara <[email protected]>
Date:   Thu Oct 20 12:26:43 2016 +0900

    ipv6: remove unnecessary control message marshaling
    
    The encoded data is just for debugging at kernel side and has
    remained in normal code path until now, oops.
    
    Change-Id: I3581bf73a6e6c9ec4b6228a670b6d8338f13ee14
    Reviewed-on: https://go-review.googlesource.com/31535
    Run-TryBot: Mikio Hara <[email protected]>
    TryBot-Result: Gobot Gobot <[email protected]>
    Reviewed-by: Ian Lance Taylor <[email protected]>

After upgrading to

$ git log -1
commit 01c190206fbdffa42f334f4b2bf2220f50e64920
Author: Tom Bergan <[email protected]>
Date:   Thu Nov 2 11:53:09 2017 -0700

    http2: fix transport data race on reused *http.Request objects
    
    Based on golang/go#19653, it should be possible to reuse an http.Request
    object after the outstanding request has completed. This CL fixes a race
    in the http/2 library that occurs when a caller tries to reuse an
    http.Request just after the request completed.
    
    The new test failed with -race before this CL and passes after this CL.
    Verified with -count 10000.
    
    Updates golang/go#21316
    
    Change-Id: I014cf9cefd0dd21f6f41763ba554d23ddc7fca40
    Reviewed-on: https://go-review.googlesource.com/75530
    Reviewed-by: Brad Fitzpatrick <[email protected]>
    Run-TryBot: Brad Fitzpatrick <[email protected]>
    TryBot-Result: Gobot Gobot <[email protected]>

The panic problem disappeared.

[bradfitz]

Thanks for confirming. I'd thought this sounded familiar. I'm going to close as already fixed in the past year. Somebody else can search/bisect to figure out the dup bug and the fix if they're curious.

[mikioh]

Dup of #19209.