cmd/pprof: runtime error: slice bounds out of range on "view source"

[prattmic]

Reported at https://groups.google.com/g/golang-dev/c/MH_e2xnSWAE/m/cCPpbtb8AQAJ

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

$ go version
go version devel go1.17-8212707871 Mon Jun 7 15:19:57 2021 +0000 linux/amd64

Does this issue reproduce with the latest release?

No

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

go env Output

$ go env
GO111MODULE=""
GOARCH="amd64"
GOBIN=""
GOCACHE="/usr/local/google/home/mpratt/.cache/go-build"
GOENV="/usr/local/google/home/mpratt/.config/go/env"
GOEXE=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOINSECURE=""
GOMODCACHE="/usr/local/google/home/mpratt/go/pkg/mod"
GONOPROXY=""
GONOSUMDB=""
GOOS="linux"
GOPATH="/usr/local/google/home/mpratt/go"
GOPRIVATE=""
GOPROXY="https://proxy.golang.org,direct"
GOROOT="/usr/local/google/home/mpratt/src/go"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/usr/local/google/home/mpratt/src/go/pkg/tool/linux_amd64"
GOVCS=""
GOVERSION="devel go1.17-8212707871 Mon Jun 7 15:19:57 2021 +0000"
GCCGO="gccgo"
AR="ar"
CC="gcc"
CXX="g++"
CGO_ENABLED="1"
GOMOD="/dev/null"
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
PKG_CONFIG="pkg-config"
GOGCCFLAGS="-fPIC -m64 -pthread -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build3999737285=/tmp/go-build -gno-record-gcc-switches"

What did you do?

https://play.golang.org/p/ASWkOjkKSN-

$ go tool pprof -http :8080 ./prof cpu.profile, then browse to http://localhost:8080/ui/source

What did you expect to see?

Source

What did you see instead?

2021/06/07 12:56:09 http: panic serving 10.129.52.196:49259: runtime error: slice bounds out of range [:18446744073705353216] with capacity 663772
goroutine 6 [running]:                                                                                                                       
net/http.(*conn).serve.func1()                                                                                                               
        /usr/local/google/home/mpratt/src/go/src/net/http/server.go:1801 +0xb9                                                 
panic({0x8e0580, 0xc0000e1770})                                                                                                              
        /usr/local/google/home/mpratt/src/go/src/runtime/panic.go:1047 +0x266     
cmd/internal/objfile.(*Disasm).Decode(0xc000119920, 0xc00031a530, 0x6, {0x0, 0x1, 0xc000198fd0}, 0xd9, 0x30)
        /usr/local/google/home/mpratt/src/go/src/cmd/internal/objfile/disasm.go:276 +0x42a                                         
main.(*objTool).Disasm(0x1, {0xc00031a530, 0x0}, 0xc00036f320, 0xc000199130, 0xd0)                                    
        /usr/local/google/home/mpratt/src/go/src/cmd/pprof/pprof.go:183 +0x9d                                            
cmd/vendor/github.com/google/pprof/driver.(*internalObjTool).Disasm(0xc000312f50, {0xc00031a530, 0x2}, 0x0, 0x1000067049a8c18, 0x0)
        /usr/local/google/home/mpratt/src/go/src/cmd/vendor/github.com/google/pprof/driver/driver.go:273 +0x3b                               
cmd/vendor/github.com/google/pprof/internal/report.(*sourcePrinter).expandAddresses(0xc00037c140, 0xc000314520, 0x0, 0x0)
        /usr/local/google/home/mpratt/src/go/src/cmd/vendor/github.com/google/pprof/internal/report/source.go:352 +0x376              
cmd/vendor/github.com/google/pprof/internal/report.newSourcePrinter(0xc000314520, {0x9f8118, 0xc000119930}, {0xc00002e0f4, 0x27})
        /usr/local/google/home/mpratt/src/go/src/cmd/vendor/github.com/google/pprof/internal/report/source.go:312 +0x5f7       
cmd/vendor/github.com/google/pprof/internal/report.PrintWebList({0x9f1320, 0xc00036eae0}, 0xc000314520, {0x9f8118, 0xc000119930}, 0x2)
        /usr/local/google/home/mpratt/src/go/src/cmd/vendor/github.com/google/pprof/internal/report/source.go:208 +0xcc
cmd/vendor/github.com/google/pprof/internal/driver.(*webInterface).source(0xc000243740, {0x9fa330, 0xc0003222a0}, 0xc0003b2200)
        /usr/local/google/home/mpratt/src/go/src/cmd/vendor/github.com/google/pprof/internal/driver/webui.go:397 +0x178                      
net/http.HandlerFunc.ServeHTTP(0x88fce0, {0x9fa330, 0xc0003222a0}, 0x7)                                               
        /usr/local/google/home/mpratt/src/go/src/net/http/server.go:2046 +0x2f                                                               
cmd/vendor/github.com/google/pprof/internal/driver.defaultWebServer.func1({0x9fa330, 0xc0003222a0}, 0xc0003b2200)
        /usr/local/google/home/mpratt/src/go/src/cmd/vendor/github.com/google/pprof/internal/driver/webui.go:190 +0xb7                                                                                                                                                                    
net/http.HandlerFunc.ServeHTTP(0x4d1bd3, {0x9fa330, 0xc0003222a0}, 0x72)                                                                     
        /usr/local/google/home/mpratt/src/go/src/net/http/server.go:2046 +0x2f                                                               
net/http.StripPrefix.func1({0x9fa330, 0xc0003222a0}, 0xc0002b8300)                                                                           
        /usr/local/google/home/mpratt/src/go/src/net/http/server.go:2089 +0x330                                                              
net/http.HandlerFunc.ServeHTTP(0xc000199b40, {0x9fa330, 0xc0003222a0}, 0x68c60f)
        /usr/local/google/home/mpratt/src/go/src/net/http/server.go:2046 +0x2f                              
net/http.(*ServeMux).ServeHTTP(0x4681ca, {0x9fa330, 0xc0003222a0}, 0xc0002b8300)          
        /usr/local/google/home/mpratt/src/go/src/net/http/server.go:2424 +0x149   
net/http.serverHandler.ServeHTTP({0xc000094570}, {0x9fa330, 0xc0003222a0}, 0x6)                                                      
        /usr/local/google/home/mpratt/src/go/src/net/http/server.go:2865 +0x8e                                                     
net/http.(*conn).serve(0xc0000960a0, {0x9fcf80, 0xc000243d70})                                                                               
        /usr/local/google/home/mpratt/src/go/src/net/http/server.go:1929 +0xb08                                                              
created by net/http.(*Server).Serve
        /usr/local/google/home/mpratt/src/go/src/net/http/server.go:2991 +0x4e8

[prattmic]

Same thing without the webserver complexity:

$ go tool pprof -weblist . ./prof cpu.profile
panic: runtime error: slice bounds out of range [:18446744073705353216] with capacity 759594

goroutine 1 [running]:
cmd/internal/objfile.(*Disasm).Decode(0xc000073930, 0xc00002b7f8, 0x6, {0x0, 0x1, 0xc0001731f8}, 0xd9, 0x30)
        /usr/local/google/home/mpratt/src/go/src/cmd/internal/objfile/disasm.go:276 +0x42a
main.(*objTool).Disasm(0x1, {0xc00002b7f8, 0x0}, 0xc00020c4e0, 0xc000173358, 0xf8)
        /usr/local/google/home/mpratt/src/go/src/cmd/pprof/pprof.go:183 +0x9d
cmd/vendor/github.com/google/pprof/driver.(*internalObjTool).Disasm(0xc000073f50, {0xc00002b7f8, 0x2}, 0x0, 0x100004b36650fd8, 0x0)
        /usr/local/google/home/mpratt/src/go/src/cmd/vendor/github.com/google/pprof/driver/driver.go:273 +0x3b
cmd/vendor/github.com/google/pprof/internal/report.(*sourcePrinter).expandAddresses(0xc000021040, 0xc00007d220, 0x0, 0x0)
        /usr/local/google/home/mpratt/src/go/src/cmd/vendor/github.com/google/pprof/internal/report/source.go:352 +0x376
cmd/vendor/github.com/google/pprof/internal/report.newSourcePrinter(0xc00007d220, {0x9f8118, 0xc000073940}, {0xc00002e0f4, 0x27})
        /usr/local/google/home/mpratt/src/go/src/cmd/vendor/github.com/google/pprof/internal/report/source.go:312 +0x5f7
cmd/vendor/github.com/google/pprof/internal/report.PrintWebList({0x9f1320, 0xc0001afad0}, 0xc00007d220, {0x9f8118, 0xc000073940}, 0x8)
        /usr/local/google/home/mpratt/src/go/src/cmd/vendor/github.com/google/pprof/internal/report/source.go:208 +0xcc
cmd/vendor/github.com/google/pprof/internal/report.printWebSource({0x9f1320, 0xc0001afad0}, 0xc0001b1540, {0x9f8118, 0xc000073940})
        /usr/local/google/home/mpratt/src/go/src/cmd/vendor/github.com/google/pprof/internal/report/source.go:125 +0x5b
cmd/vendor/github.com/google/pprof/internal/report.Generate({0x9f1320, 0xc0001afad0}, 0x0, {0x9f8118, 0xc000073940})
        /usr/local/google/home/mpratt/src/go/src/cmd/vendor/github.com/google/pprof/internal/report/report.go:115 +0x1c5
cmd/vendor/github.com/google/pprof/internal/driver.generateReport(_, {_, _, _}, {{0x0, 0x0}, 0x0, 0x0, {0x9123ec, 0x7}, ...}, ...)
        /usr/local/google/home/mpratt/src/go/src/cmd/vendor/github.com/google/pprof/internal/driver/driver.go:117 +0xd4
cmd/vendor/github.com/google/pprof/internal/driver.PProf(0xc000176980)
        /usr/local/google/home/mpratt/src/go/src/cmd/vendor/github.com/google/pprof/internal/driver/driver.go:53 +0x225
cmd/vendor/github.com/google/pprof/driver.PProf(0x4601db)
        /usr/local/google/home/mpratt/src/go/src/cmd/vendor/github.com/google/pprof/driver/driver.go:33 +0x1e
main.main()
        /usr/local/google/home/mpratt/src/go/src/cmd/pprof/pprof.go:38 +0xc5

[cherrymui]

It is interesting that list doesn't panic, whereas weblist does...

[prattmic]

I don't think list invokes the disassembler, while weblist does.

The immediate problem seems to be that vendored pprof is invoking cmd/pprof.objTool.Disasm with start 0x401000, end 0x0.

Still digging into why that is.

[ALTree]

A possible culprit is 68327e1. Does reverting it fixes it?

[prattmic]

I believe the problem is that https://go-review.googlesource.com/c/go/+/318049/3/src/cmd/pprof/pprof.go makes ObjAddr unconditionally return 0, but https://go-review.googlesource.com/c/go/+/318049/3/src/cmd/vendor/github.com/google/pprof/internal/report/source.go passes the result of ObjAddr to Disasm as-is. I believe that ObjAddr should return addr to remain a no-op as before.

[prattmic]

Yup, that does it. I'll send a CL.

[gopherbot]

Change https://golang.org/cl/325809 mentions this issue: cmd/pprof: make ObjAddr a no-op