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