cmd/go: panic in cmd/go/internal/cache.(*DiskCache).markUsed

[FiloSottile]

Go version

go version devel go1.24-733df2bc0a Mon Nov 25 02:23:41 2024 +0000 darwin/arm64

Output of go env in your module/workspace:

GONOPROXY='github.com/FiloSottile/*,filippo.io/*'
GOPROXY='https://proxy.golang.org'

What did you do?

$ go test crypto/internal/fips140/bigmod

What did you see happen?

Tests run.

What did you expect to see?

panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x2 addr=0x18 pc=0x104b03b30]

goroutine 690 [running]:
cmd/go/internal/cache.(*DiskCache).markUsed(0x1400000c2d0, {0x140009860e0, 0x6c})
	/Users/filippo/go/src/cmd/go/internal/cache/cache.go:366 +0xf0
cmd/go/internal/cache.(*DiskCache).OutputFile(0x1400000c2d0, {0xc9, 0xe6, 0x6, 0xd0, 0x4, 0xcc, 0x52, 0xdc, 0x1c, ...})
	/Users/filippo/go/src/cmd/go/internal/cache/cache.go:317 +0x58
cmd/go/internal/cache.GetFile({0x105102cc0, 0x1400000c2d0}, {0x69, 0xec, 0x92, 0x5b, 0xa7, 0x87, 0x5, 0x8e, ...})
	/Users/filippo/go/src/cmd/go/internal/cache/cache.go:270 +0xc4
cmd/go/internal/work.(*Builder).vet(0x14000278480, {0x23?, 0x0?}, 0x1400018f4a0)
	/Users/filippo/go/src/cmd/go/internal/work/exec.go:1329 +0x5bc
cmd/go/internal/work.ActorFunc.Act(0x1051023a0?, 0x1055150c0?, {0x1051023a0?, 0x1055150c0?}, 0x140000abf88?)
	/Users/filippo/go/src/cmd/go/internal/work/action.go:76 +0x3c
cmd/go/internal/work.(*Builder).Do.func3({0x1051023a0, 0x1055150c0}, 0x1400018f4a0)
	/Users/filippo/go/src/cmd/go/internal/work/exec.go:153 +0x710
cmd/go/internal/work.(*Builder).Do.func4()
	/Users/filippo/go/src/cmd/go/internal/work/exec.go:225 +0x94
created by cmd/go/internal/work.(*Builder).Do in goroutine 1
	/Users/filippo/go/src/cmd/go/internal/work/exec.go:211 +0x308

[gabyhelp]

Related Issues

• cmd/go: panic in 'go work use' #50958 (closed)
• cmd/go: panic when building a `main` package in GOPATH mode when a go.work file exists #58767 (closed)
• cmd/go/internal/work: panic for a repeated //go:debug directive for the same setting #62346 (closed)
• cmd/go: workspace recursive add panics on permission errors #51960 (closed)
• cmd/go: panic: runtime error: invalid memory address or nil pointer dereference during type checking in `go generate` #66670 (closed)
• x/tools/go/packages: nil pointer dereference #69524 (closed)
• go/types: SIGSEGV in (*Checker).exprInternal #37602
• cmd/go: go work use panics when given a file #51749 (closed)
• fmt: Panic within fmt.Sprintf() #64505 (closed)
• text/template: panics encountered during function calls are hard to treat and debug #28242 (closed)

_{(Emoji vote if this was helpful or unhelpful; more detailed feedback welcome in this discussion.)}

[FiloSottile]

I needed to make progress so I emptied GOCACHE, which solved the issue. I kept a copy of the old one if you need.

[rolandshoemaker]

cc @matloob, possibly related to the #69290 work.

[adonovan]

I'm hitting this too, reproducibly. There's a missing err==nil check before using info in this code:

// markUsed reports whether the file is a directory (an executable cache entry).
func (c *DiskCache) markUsed(file string) (isExecutable bool) {
	info, err := os.Stat(file)
	if err == nil && c.now().Sub(info.ModTime()) < mtimeInterval {
		return info.IsDir()
	}
	os.Chtimes(file, c.now(), c.now())
	return info.IsDir()
}

[gopherbot]

Change https://go.dev/cl/633037 mentions this issue: cmd/go/internal/cache: always check error from stat in markUsed

[mknyszek]

RC1 is currently planned for next week. Is this OK to land after the RC, or does it block the RC? If it blocks the RC, we should prioritize moving the fix forward. Thanks.

[adonovan]

This fix should definitely be in the RC.