go1.21 regression: SIGSEGV in testing.(*common).decorate

[rfjakob]

Summary: Looks like 81316ff broke gocryptfs -speed . Downstream ticket: rfjakob/gocryptfs#789

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

$ go version
go version go1.21.1 linux/amd64

Does this issue reproduce with the latest release?

Yes

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

go env Output

$ go env
GO111MODULE=''
GOARCH='amd64'
GOBIN=''
GOCACHE='/home/jakob/.cache/go-build'
GOENV='/home/jakob/.config/go/env'
GOEXE=''
GOEXPERIMENT=''
GOFLAGS=''
GOHOSTARCH='amd64'
GOHOSTOS='linux'
GOINSECURE=''
GOMODCACHE='/home/jakob/go/pkg/mod'
GONOPROXY=''
GONOSUMDB=''
GOOS='linux'
GOPATH='/home/jakob/go'
GOPRIVATE=''
GOPROXY='https://proxy.golang.org,direct'
GOROOT='/usr/local/go'
GOSUMDB='sum.golang.org'
GOTMPDIR=''
GOTOOLCHAIN='auto'
GOTOOLDIR='/usr/local/go/pkg/tool/linux_amd64'
GOVCS=''
GOVERSION='go1.21.1'
GCCGO='gccgo'
GOAMD64='v1'
AR='ar'
CC='gcc'
CXX='g++'
CGO_ENABLED='1'
GOMOD='/home/jakob/go/src/github.com/rfjakob/gocryptfs/go.mod'
GOWORK=''
CGO_CFLAGS='-O2 -g'
CGO_CPPFLAGS=''
CGO_CXXFLAGS='-O2 -g'
CGO_FFLAGS='-O2 -g'
CGO_LDFLAGS='-O2 -g'
PKG_CONFIG='pkg-config'
GOGCCFLAGS='-fPIC -m64 -pthread -Wl,--no-gc-sections -fmessage-length=0 -ffile-prefix-map=/tmp/go-build1209216281=/tmp/go-build -gno-record-gcc-switches'

What did you do?

git clone https://github.com/rfjakob/gocryptfs.git
cd gocryptfs
./build-without-openssl.bash
./gocryptfs -speed

What did you expect to see?

./gocryptfs -speed
gocryptfs v2.4.0-4-g7fff33a without_openssl; go-fuse v2.3.0; 2023-09-15 go1.20.3 linux/amd64
cpu: Intel(R) Core(TM) i5-3470 CPU @ 3.20GHz; with AES acceleration
AES-GCM-256-OpenSSL       	    N/A
AES-GCM-256-Go            	 999.53 MB/s	(selected in auto mode)
AES-SIV-512-Go            	 159.86 MB/s
XChaCha20-Poly1305-OpenSSL	    N/A
XChaCha20-Poly1305-Go     	 835.61 MB/s	(selected in auto mode)

What did you see instead?

./gocryptfs -speed
gocryptfs v2.4.0-4-g7fff33a without_openssl; go-fuse v2.3.0; 2023-09-15 go1.21.1 linux/amd64
cpu: Intel(R) Core(TM) i5-3470 CPU @ 3.20GHz; with AES acceleration
AES-GCM-256-OpenSSL       	panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x0 pc=0x5a5de0]

goroutine 19 [running]:
testing.(*common).decorate(0x40d625?, {0xc00001c180, 0x2a}, 0x830601?)
	testing/testing.go:772 +0xa0
testing.(*common).logDepth(0xc0000ea280, {0xc00001c180, 0x2a}, 0x3)
	testing/testing.go:1035 +0x1dd
testing.(*common).log(...)
	testing/testing.go:1004
testing.(*common).Skip(0xc0000ea280, {0xc00003ef08?, 0x48874f?, 0xc00003ef18?})
	testing/testing.go:1089 +0x4a
github.com/rfjakob/gocryptfs/v2/internal/speed.bStupidGCM(0xc0000ea280)
	github.com/rfjakob/gocryptfs/v2/internal/speed/speed.go:129 +0x45
testing.(*B).runN(0xc0000ea280, 0x1)
	testing/benchmark.go:193 +0x102
testing.(*B).run1.func1()
	testing/benchmark.go:233 +0x4e
created by testing.(*B).run1 in goroutine 1
	testing/benchmark.go:226 +0x90

[rfjakob]

gdb:

/usr/local/go/src$ gdb --args gocryptfs /home/jakob/go/src/github.com/rfjakob/gocryptfs -speed
[...]
Reading symbols from gocryptfs...
Loading Go Runtime support.
(gdb) r
Starting program: /ssd2/jakob.donotbackup/go/bin/gocryptfs /home/jakob/go/src/github.com/rfjakob/gocryptfs -speed
[...]
[New LWP 121475]
[New LWP 121476]
[New LWP 121477]
[New LWP 121478]
gocryptfs v2.4.0-4-g7fff33a without_openssl; go-fuse v2.3.0; 2023-09-15 go1.21.1 linux/amd64
cpu: Intel(R) Core(TM) i5-3470 CPU @ 3.20GHz; with AES acceleration
AES-GCM-256-OpenSSL       	[New LWP 121479]

Thread 4 "gocryptfs" received signal SIGSEGV, Segmentation fault.
[Switching to LWP 121477]
0x00000000005a5de0 in testing.(*common).decorate (c=<optimized out>, 
    s="openssl has been disabled at compile-time\n", skip=<optimized out>, ~r0=...)
    at testing/testing.go:772
772			if *fullPath {
(gdb) l
767	func (c *common) decorate(s string, skip int) string {
768		frame := c.frameSkip(skip)
769		file := frame.File
770		line := frame.Line
771		if file != "" {
772			if *fullPath {
773				// If relative path, truncate file name at last file name separator.
774			} else if index := strings.LastIndex(file, "/"); index >= 0 {
775				file = file[index+1:]
776			} else if index = strings.LastIndex(file, "\\"); index >= 0 {

[rfjakob]

Looks like I should have been calling testing.Init(), so this panic is OK as per the docs.

I do now call testing.Init(), and this fixes the issue, so I'm closing the ticket. Maybe other people hitting this will find the commit useful: rfjakob/gocryptfs@3a65627