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cmd/link: runtime crash, unexpected fault address 0xffffffffffffffff, h2_bundle.go, when using plugin #44586

parsley42 opened this issue Feb 24, 2021 · 11 comments


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@parsley42 parsley42 commented Feb 24, 2021

What version of Go are you using (go version)?

$ go version
go version go1.16 linux/amd64

Does this issue reproduce with the latest release?


What operating system and processor architecture are you using (go env)?

go env Output
$ go env
GOGCCFLAGS="-fPIC -m64 -pthread -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build42897677=/tmp/go-build -gno-record-gcc-switches"

What did you do?

I'm going to need some suggestions on figuring out what happened, but the gist is I ran my program and it crashed with a strange segfault.

What did you expect to see?

Program running as it did with Go 1.15.8.

What did you see instead?

My program crashed with a segmentation violation; I've pasted in the stack trace (in a details section) below.

./gopherbot stack trace
2021/02/24 13:38:50 Info: Listening for external plugin connections on
unexpected fault address 0xffffffffffffffff
fatal error: fault
[signal SIGSEGV: segmentation violation code=0x1 addr=0xffffffffffffffff pc=0xffffffffffffffff]

goroutine 71 [running]:
runtime.throw(0x9e75e8, 0x5)
/usr/local/go/src/runtime/panic.go:1117 +0x72 fp=0xc00004ac70 sp=0xc00004ac40 pc=0x56c752
/usr/local/go/src/runtime/signal_unix.go:741 +0x268 fp=0xc00004aca8 sp=0xc00004ac70 pc=0x5836e8
net/http.(*http2clientStream).writeRequestBody.func1(0xc000130420, 0xc00004af90, 0x7f281410c638, 0xc000218708)
/usr/local/go/src/net/http/h2_bundle.go:7825 +0x5a fp=0xc00004acd0 sp=0xc00004aca8 pc=0x7f28158a6e9a
net/http.(*http2clientStream).writeRequestBody(0xc000130420, 0xa755e0, 0xc000218708, 0x7f281410c638, 0xc000218708, 0x0, 0x0)
/usr/local/go/src/net/http/h2_bundle.go:7903 +0xe04 fp=0xc00004af68 sp=0xc00004acd0 pc=0x7f281587ce64
/usr/local/go/src/net/http/h2_bundle.go:9114 +0xcc fp=0xc00004afe0 sp=0xc00004af68 pc=0x7f28158a7d6c
/usr/local/go/src/runtime/asm_amd64.s:1371 +0x1 fp=0xc00004afe8 sp=0xc00004afe0 pc=0x5a3d01
created by net/http.http2bodyWriterState.scheduleBodyWrite
/usr/local/go/src/net/http/h2_bundle.go:9163 +0xa6

goroutine 1 [chan receive]:, 0xcdf0d8, 0xc00006ee60, 0x5, 0xc00007b418)
/home/parse/git/gopher/gopherbot/connectors/slack/connect.go:76 +0x2ce, 0x2, 0xa6c530, 0x8)
/home/parse/git/gopher/gopherbot/bot/start.go:370 +0x1482
/home/parse/git/gopher/gopherbot/main.go:16 +0x51

goroutine 10 [IO wait]:
internal/poll.runtime_pollWait(0x7f2815e50858, 0x72, 0x0)
/usr/local/go/src/runtime/netpoll.go:222 +0x55
internal/poll.(*pollDesc).wait(0xc000224118, 0x72, 0x0, 0x0, 0x9e7df8)
/usr/local/go/src/internal/poll/fd_poll_runtime.go:87 +0x45
internal/poll.(*FD).Accept(0xc000224100, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0)
/usr/local/go/src/internal/poll/fd_unix.go:401 +0x212
net.(*netFD).accept(0xc000224100, 0x30, 0x30, 0x7f283eb06a68)
/usr/local/go/src/net/fd_unix.go:172 +0x45
net.(*TCPListener).accept(0xc000218048, 0xc000048db0, 0x7f28145e163a, 0x30)
/usr/local/go/src/net/tcpsock_posix.go:139 +0x32
net.(*TCPListener).Accept(0xc000218048, 0x9b8460, 0xc000207230, 0x975940, 0xc66a90)
/usr/local/go/src/net/tcpsock.go:261 +0x65
net/http.(*Server).Serve(0xc000232000, 0xa7b220, 0xc000218048, 0x0, 0x0)
/usr/local/go/src/net/http/server.go:2981 +0x2a3
net/http.(*Server).ListenAndServe(0xc000232000, 0xc000232000, 0xc000208290)
/usr/local/go/src/net/http/server.go:2910 +0xbc
/home/parse/git/gopher/gopherbot/history/file/filehistory.go:185 +0x15d
created by
/home/parse/git/gopher/gopherbot/history/file/filehistory.go:183 +0x3a8

goroutine 98 [IO wait]:
internal/poll.runtime_pollWait(0x7f2815e50688, 0x72, 0x0)
/usr/local/go/src/runtime/netpoll.go:222 +0x55
internal/poll.(*pollDesc).wait(0xc0002df398, 0x72, 0x0, 0x0, 0x9e7df8)
/usr/local/go/src/internal/poll/fd_poll_runtime.go:87 +0x45
internal/poll.(*FD).Accept(0xc0002df380, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0)
/usr/local/go/src/internal/poll/fd_unix.go:401 +0x212
net.(*netFD).accept(0xc0002df380, 0x30, 0x30, 0x7f283eb06a68)
/usr/local/go/src/net/fd_unix.go:172 +0x45
net.(*TCPListener).accept(0xc000218630, 0xc000049e08, 0x5445b8, 0x30)
/usr/local/go/src/net/tcpsock_posix.go:139 +0x32
net.(*TCPListener).Accept(0xc000218630, 0x9b8460, 0xc0004091a0, 0x975940, 0xc66a90)
/usr/local/go/src/net/tcpsock.go:261 +0x65
net/http.(*Server).Serve(0xc0002320e0, 0xa7b220, 0xc000218630, 0x0, 0x0)
/usr/local/go/src/net/http/server.go:2981 +0x285
/usr/local/go/src/net/http/server.go:2529, 0xc000218630)
/home/parse/git/gopher/gopherbot/bot/bot_process.go:227 +0x158
created by
/home/parse/git/gopher/gopherbot/bot/bot_process.go:222 +0x615

goroutine 99 [select]:
net/http.(*http2ClientConn).roundTrip(0xc000244480, 0xc00016c200, 0x0, 0x0, 0x0, 0x0)
/usr/local/go/src/net/http/h2_bundle.go:7668 +0x9bc
net/http.(*http2Transport).RoundTripOpt(0xc0000fbc70, 0xc00016c200, 0x7f2815af4900, 0xc0006e4f20, 0x7f2815af49f0, 0xa0e670)
/usr/local/go/src/net/http/h2_bundle.go:6981 +0x1a5
net/http.(*http2Transport).RoundTrip(0xc0000fbc70, 0xc00016c200, 0x0, 0xc000699170, 0x5)
/usr/local/go/src/net/http/h2_bundle.go:6942 +0x3c
net/http.(*Transport).roundTrip(0x7f2815af49c0, 0xc00016c100, 0xc0006e66e0, 0x160, 0x150)
/usr/local/go/src/net/http/transport.go:590 +0x845
net/http.(*Transport).RoundTrip(0x7f2815af49c0, 0xc00016c100, 0x7f2815af49c0, 0x0, 0x0)
/usr/local/go/src/net/http/roundtrip.go:17 +0x37
net/http.send(0xc00016c100, 0x7f281599cec8, 0x7f2815af49c0, 0x0, 0x0, 0x0, 0xc0002f03a8, 0x9e8e25, 0x1, 0x0)
/usr/local/go/src/net/http/client.go:251 +0x466
net/http.(*Client).send(0xc0000793b0, 0xc00016c100, 0x0, 0x0, 0x0, 0xc0002f03a8, 0x0, 0x1, 0xe)
/usr/local/go/src/net/http/client.go:175 +0xff
net/http.(*Client).do(0xc0000793b0, 0xc00016c100, 0x0, 0x0, 0x0)
/usr/local/go/src/net/http/client.go:717 +0x46f
net/http.(*Client).Do(0xc0000793b0, 0xc00016c100, 0xc0006f9810, 0x7f2814dc861a, 0x18)
/usr/local/go/src/net/http/client.go:585 +0x37, 0xc0004c9500, 0x7f2815213a58, 0xc0000793b0, 0xc00016c000, 0xc0002186d8, 0x7f28152190f0, 0xc00019fee0, 0x0, 0x0)
/home/parse/git/gopher/gopherbot/vendor/ +0x10a, 0xc0004c9500, 0x7f2815213a58, 0xc0000793b0, 0xc000699170, 0x21, 0xc00004f9a0, 0x7f28151ccee0, 0xc0004b6fc0, 0x7f28152190f0, ...)
/home/parse/git/gopher/gopherbot/vendor/ +0x27a*Client).postMethod(...)
/home/parse/git/gopher/gopherbot/vendor/*Client).ConnectRTMContext(0xc00019fee0, 0xa7bfe8, 0xc0004c9500, 0xa7bfe8, 0xc0004c9500, 0xc000209640, 0x54b6cc, 0x7f2816e85868)
/home/parse/git/gopher/gopherbot/vendor/ +0x225*Client).ConnectRTM(0xc00019fee0, 0x0, 0x0, 0x0, 0x0, 0x0)
/home/parse/git/gopher/gopherbot/vendor/ +0xac*RTM).startRTMAndDial(0xc00019fee0, 0xc0005af600, 0x0, 0x0, 0x0, 0x0)
/home/parse/git/gopher/gopherbot/vendor/ +0x5c5*RTM).connect(0xc00019fee0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0)
/home/parse/git/gopher/gopherbot/vendor/ +0x127*RTM).ManageConnection(0xc00019fee0)
/home/parse/git/gopher/gopherbot/vendor/ +0x65
created by
/home/parse/git/gopher/gopherbot/connectors/slack/connect.go:69 +0x258

goroutine 70 [IO wait]:
internal/poll.runtime_pollWait(0x7f2815e50770, 0x72, 0xffffffffffffffff)
/usr/local/go/src/runtime/netpoll.go:222 +0x55
internal/poll.(*pollDesc).wait(0xc0002df798, 0x72, 0x1000, 0x1010, 0xffffffffffffffff)
/usr/local/go/src/internal/poll/fd_poll_runtime.go:87 +0x45
internal/poll.(*FD).Read(0xc0002df780, 0xc0000da000, 0x1010, 0x1010, 0x0, 0x0, 0x0)
/usr/local/go/src/internal/poll/fd_unix.go:166 +0x1d5
net.(*netFD).Read(0xc0002df780, 0xc0000da000, 0x1010, 0x1010, 0xc0006964c8, 0x18, 0x155)
/usr/local/go/src/net/fd_posix.go:55 +0x4f
net.(*conn).Read(0xc000204228, 0xc0000da000, 0x1010, 0x1010, 0x0, 0x0, 0x0)
/usr/local/go/src/net/net.go:183 +0x91
crypto/tls.(*atLeastReader).Read(0xc00041c000, 0xc0000da000, 0x1010, 0x1010, 0x0, 0xc00003e800, 0x0)
/usr/local/go/src/crypto/tls/conn.go:776 +0x63
bytes.(*Buffer).ReadFrom(0xc00007e978, 0xa74f80, 0xc00041c000, 0x541be5, 0x983760, 0x9d14c0)
/usr/local/go/src/bytes/buffer.go:204 +0xbe
crypto/tls.(*Conn).readFromUntil(0xc00007e700, 0xa75460, 0xc000204228, 0x5, 0xc000204228, 0x0)
/usr/local/go/src/crypto/tls/conn.go:798 +0xf3
crypto/tls.(*Conn).readRecordOrCCS(0xc00007e700, 0x0, 0x0, 0x7f2815636955)
/usr/local/go/src/crypto/tls/conn.go:605 +0x115
crypto/tls.(*Conn).Read(0xc00007e700, 0xc000478000, 0x1000, 0x1000, 0x0, 0x0, 0x0)
/usr/local/go/src/crypto/tls/conn.go:1276 +0x165
bufio.(*Reader).Read(0xc00020cd20, 0xc0002323b8, 0x9, 0x9, 0xc0005b3458, 0x7f281562e20f, 0x9ca320)
/usr/local/go/src/bufio/bufio.go:227 +0x222
io.ReadAtLeast(0xa74e40, 0xc00020cd20, 0xc0002323b8, 0x9, 0x9, 0x9, 0x0, 0x0, 0x0)
/usr/local/go/src/io/io.go:328 +0x89
net/http.http2readFrameHeader(0xc0002323b8, 0x9, 0x9, 0xa74e40, 0xc00020cd20, 0x0, 0x0, 0x0, 0x0)
/usr/local/go/src/net/http/h2_bundle.go:1477 +0x89
net/http.(*http2Framer).ReadFrame(0xc000232380, 0x0, 0x0, 0x0, 0x0)
/usr/local/go/src/net/http/h2_bundle.go:1735 +0xa7
net/http.(*http2clientConnReadLoop).run(0xc0000d5fa8, 0x0, 0x0)
/usr/local/go/src/net/http/h2_bundle.go:8322 +0xda
/usr/local/go/src/net/http/h2_bundle.go:8244 +0x71
created by net/http.(*http2Transport).newClientConn
/usr/local/go/src/net/http/h2_bundle.go:7208 +0x6f7

Note that if I run the same program with a different configuration (connecting to Slack or not, but so far I've had no luck in finding a the causal link), it doesn't crash. Hopefully someone more knowledgeable than I can make some sense of the dump and suggest something to look for in my code - but the actual thread that crashed appears to have been created entirely within the runtime, so I'm at a loss.

@seankhliao seankhliao changed the title 1.15.8 -> 1.16 regression, runtime crash, unexpected fault address 0xffffffffffffffff, h2_bundle.go runtime: crash, unexpected fault address 0xffffffffffffffff, h2_bundle.go Feb 24, 2021
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@cherrymui cherrymui commented Feb 25, 2021

One possibility where this address can come up is that a method is called which the linker decided unreachable, possibly a linker bug. At h2_bundle.go:7825 it seems an interface method call of the Close method. Do you know what the concrete type that interface value is? Is it possible to share the whole program? Thanks.

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@parsley42 parsley42 commented Feb 25, 2021

Well, the whole program is Gopherbot -

All the http code is either in the /bot subdirectory or vendor/

Is there a debug flag I can pass during build that might catch this during linking?

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@cherrymui cherrymui commented Feb 25, 2021

At the moment it is probably most useful to know what the concrete type is. Maybe you can add a print, something like

diff --git a/src/net/http/h2_bundle.go b/src/net/http/h2_bundle.go
index 6bef310feb..0588d6e5cb 100644
--- a/src/net/http/h2_bundle.go
+++ b/src/net/http/h2_bundle.go
@@ -7820,6 +7820,7 @@ func (cs *http2clientStream) writeRequestBody(body io.Reader, bodyCloser io.Clos
                // Request.Body is closed by the Transport,
                // and in multiple cases: server replies <=299 and >299
                // while still writing request body
+               fmt.Printf("XXX bodyCloser type %T\n", bodyCloser)
                cerr := bodyCloser.Close()
                if err == nil {
                        err = cerr

There are linker debug flags but it is not that helpful without knowing the type.

Also, it would be helpful to know how the program is built, e.g. a static executable, or with shared libraries, or plugins. Thanks.

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@parsley42 parsley42 commented Feb 25, 2021

Huh. Never realized I could just edit files in /usr/local/go/src/..., but yeah, that worked:

XXX bodyCloser type *http.readTrackingBody
unexpected fault address 0xffffffffffffffff

Here's an excerpt from make showing how it's compiled (with plugins):

# Compling the main binary
CGO_ENABLED=1 GOOS=linux GOARCH=amd64 go build -mod vendor -ldflags "-s -w -X main.Commit=9f2aab10" -tags "netgo osusergo static_build modular" -o gopherbot
# Compiling the "slack" module
GOOS=linux GOARCH=amd64 go build -mod vendor -ldflags "-s -w" -o connectors/ -buildmode=plugin -tags 'netgo osusergo static_build module' connectors/slack-mod.go

Thanks for digging in to this.

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@cherrymui cherrymui commented Feb 26, 2021

Thanks for the information. This is helpful. Could you try CL ? It should apply cleanly to Go 1.16. Thanks.

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@gopherbot gopherbot commented Feb 26, 2021

Change mentions this issue: cmd/link: handle types as converted to interface when dynlink

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@parsley42 parsley42 commented Feb 26, 2021

Ok, I ended up cloning & building go from source (after git checkout go1.16), and indeed this fixes it. Thanks.

I assume this will eventually show up in a merged PR with fixes #..., so I'll leave this open for automatic close.

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@cherrymui cherrymui commented Feb 26, 2021

Thanks for confirming. Yes, it will.

@cherrymui cherrymui changed the title runtime: crash, unexpected fault address 0xffffffffffffffff, h2_bundle.go cmd/link: runtime crash, unexpected fault address 0xffffffffffffffff, h2_bundle.go, when using plugin Feb 26, 2021
@gopherbot gopherbot closed this in a655208 Feb 26, 2021
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@cherrymui cherrymui commented Feb 26, 2021

@gopherbot please backport this to Go 1.16. This is a regression causing runtime crash without easy workaround.

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@gopherbot gopherbot commented Feb 26, 2021

Backport issue(s) opened: #44638 (for 1.16).

Remember to create the cherry-pick CL(s) as soon as the patch is submitted to master, according to

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@gopherbot gopherbot commented Feb 26, 2021

Change mentions this issue: [release-branch.go1.16] cmd/link: handle types as converted to interface when dynlink

@dmitshur dmitshur added this to the Go1.17 milestone Mar 1, 2021
gopherbot pushed a commit that referenced this issue Mar 1, 2021
…ace when dynlink

When using plugins, a type (whose value) may be pass to a plugin
and get converted to interface there, or vice versa. We need to
treat the type as potentially converted to interface, and retain
its methods.

Updates #44586.
Fixes #44638.

Change-Id: I80dd35e68baedaa852a317543ccd78d94628d13b
Trust: Cherry Zhang <>
Run-TryBot: Cherry Zhang <>
TryBot-Result: Go Bot <>
Reviewed-by: Than McIntosh <>
(cherry picked from commit a655208)
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5 participants