Stash crashes when scanning, bringing down the entire container

General Discussions
1

When scanning my library, stash crashes with an index out of bounds error. It brings the entire stash container down, terminating stash. stash is unusable in this form.

logs :

INFO[2026-01-21 07:38:47] Calculating fingerprints for /data/Tigresavip.com.br Siterip/Flakael mete na minha buceta e depois gosa na minha boca.mp4 ... 
INFO[2026-01-21 07:38:48] /media/XXX/video/Tigresavip.com.br Siterip/Estava lavando louça chegou Veltin e Flakael, transei com os dois ali mesmo rolou até dupla penetração.mp4 moved to /data/Tigresavip.com.br Siterip/Estava lavando louça chegou Veltin e Flakael, transei com os dois ali mesmo rolou até dupla penetração.mp4. Updating path... 
INFO[2026-01-21 07:38:48] Calculating fingerprints for /data/Tigresavip.com.br Siterip/Fui no quarto dos meninos ai Veltin e Flakael quis me comer, metemos mais de hora e rolou aquela D.P deliciosas com as.mp4 ... 
panic: runtime error: index out of range [155] with length 155 [recovered]
        panic: runtime error: index out of range [155] with length 155

goroutine 9928 [running]:
github.com/stashapp/stash/pkg/txn.withTxn.func1()
        github.com/stashapp/stash/pkg/txn/transaction.go:65 +0x2f3
panic({0x14b44f22eaa0?, 0xc004cc98a8?})
        runtime/panic.go:792 +0x132
github.com/stashapp/stash/pkg/fsutil.IsFsPathCaseSensitive({0xc00c8280a0, 0x9b})
        github.com/stashapp/stash/pkg/fsutil/fs.go:37 +0x293
github.com/stashapp/stash/pkg/file.(*OsFS).IsPathCaseSensitive(0xc0002b5d40?, {0xc00c8280a0?, 0xc0061a0ab0?})
        github.com/stashapp/stash/pkg/file/fs.go:66 +0x1e
github.com/stashapp/stash/pkg/file.(*scanJob).handleFolder.func1({0x14b44f33b410, 0xc0061a0ab0})
        github.com/stashapp/stash/pkg/file/scan.go:511 +0x16e
github.com/stashapp/stash/pkg/txn.withTxn({0x14b44f33b448, 0xc001a0e000}, {0x14b44f33b120, 0xc00036bb00}, 0xc003a57778, 0x80?, 0x0)
        github.com/stashapp/stash/pkg/txn/transaction.go:89 +0x177
github.com/stashapp/stash/pkg/txn.Retryer.WithTxn({{0x14b44f33b120?, 0xc00036bb00?}, 0xb0?, 0x0?}, {0x14b44f33b448, 0xc001a0e000}, 0xc003a57778)
        github.com/stashapp/stash/pkg/txn/transaction.go:156 +0xe6
github.com/stashapp/stash/pkg/file.(*scanJob).withTxn(...)
        github.com/stashapp/stash/pkg/file/scan.go:164
github.com/stashapp/stash/pkg/file.(*scanJob).handleFolder(0xc00c8280a0?, {0x14b44f33b448?, 0xc001a0e000?}, {0xc00adee420, {0x14b44f33cc40, 0x14b450371120}, {0x14b44f33e550, 0xc00ef9a000}})
        github.com/stashapp/stash/pkg/file/scan.go:497 +0xf4
github.com/stashapp/stash/pkg/file.(*scanJob).queueFiles.func1.(*scanJob).queueFileFunc.1({0xc00c8280a0, 0x9b}, {0x14b44f33b078, 0xc00addc500}, {0x0?, 0x0?})
        github.com/stashapp/stash/pkg/file/scan.go:282 +0x6f4
github.com/stashapp/stash/pkg/file.walkSym.func1({0xc00c828000?, 0x9a?}, {0x14b44f33b078, 0xc00addc500}, {0x0, 0x0})
        github.com/stashapp/stash/pkg/file/walk.go:79 +0x244
github.com/stashapp/stash/pkg/file.walkDir({0x14b44f33cc40, 0x14b450371120}, {0xc00c828000, 0x9b}, {0x14b44f33b078, 0xc00addc500}, 0xc003a57dd8)
        github.com/stashapp/stash/pkg/file/walk.go:112 +0x6c
github.com/stashapp/stash/pkg/file.walkDir({0x14b44f33cc40, 0x14b450371120}, {0xc00f280660, 0x56}, {0x14b44f33b078, 0xc00aa1b340}, 0xc003a57dd8)
        github.com/stashapp/stash/pkg/file/walk.go:136 +0x265
github.com/stashapp/stash/pkg/file.walkDir({0x14b44f33cc40, 0x14b450371120}, {0xc000e0c708, 0x16}, {0x14b44f33b078, 0xc00aa79140}, 0xc003a57dd8)
        github.com/stashapp/stash/pkg/file/walk.go:136 +0x265
github.com/stashapp/stash/pkg/file.walkDir({0x14b44f33cc40, 0x14b450371120}, {0xc007b3a8e0, 0xc}, {0x14b44f33b078, 0xc00118f040}, 0xc003a57dd8)
        github.com/stashapp/stash/pkg/file/walk.go:136 +0x265
github.com/stashapp/stash/pkg/file.walkDir({0x14b44f33cc40, 0x14b450371120}, {0xc000012320, 0x5}, {0x14b44f33ba08, 0xc000546430}, 0xc003a57dd8)
        github.com/stashapp/stash/pkg/file/walk.go:136 +0x265
github.com/stashapp/stash/pkg/file.fsWalk({0x14b44f33cc40, 0x14b450371120}, {0xc000012320, 0x5}, 0xc000d69dd8)
        github.com/stashapp/stash/pkg/file/walk.go:103 +0xdf
github.com/stashapp/stash/pkg/file.walkSym({0x14b44f33cc40?, 0x14b450371120?}, {0xc000012320?, 0xc001312060?}, {0xc000012320?, 0xc000546420?}, 0x10?)
        github.com/stashapp/stash/pkg/file/walk.go:81 +0x7c
github.com/stashapp/stash/pkg/file.symWalk(...)
        github.com/stashapp/stash/pkg/file/walk.go:86
github.com/stashapp/stash/pkg/file.(*scanJob).queueFiles.func1()
        github.com/stashapp/stash/pkg/file/scan.go:210 +0xe8
github.com/stashapp/stash/pkg/job.(*Progress).ExecuteTask(0xc001a0e050, {0x14b44e3d5f35, 0x16}, 0xc00118e340)
        github.com/stashapp/stash/pkg/job/progress.go:175 +0xb2
github.com/stashapp/stash/pkg/file.(*scanJob).queueFiles(0xc000176000, {0x14b44f33b448, 0xc001a0e000}, {0xc000bb2380, 0x1, 0x1})
        github.com/stashapp/stash/pkg/file/scan.go:208 +0xe9
github.com/stashapp/stash/pkg/file.(*scanJob).execute.func1()
        github.com/stashapp/stash/pkg/file/scan.go:182 +0x65
created by github.com/stashapp/stash/pkg/file.(*scanJob).execute in goroutine 9409
        github.com/stashapp/stash/pkg/file/scan.go:180 +0x215

I opened a ticket, but @feederbox826 indicated stash doesn’t support Btrfs. I use btrfs for cache in my unraid setup. Realistically, what is my path forward to getting stash working on unraid?

2

I think I may have found the actual bug - it’s not Btrfs-specific, it’s a Unicode handling issue in the case sensitivity check.

Looking at the error index out of range [155] with length 155 at fsutil/fs.go:37, this happens in IsFsPathCaseSensitive() where the code copies bytes from a case-flipped filename into a fixed-length byte array. The problem: when certain Unicode characters are uppercased or lowercased, they can change byte length in UTF-8.

I noticed your filenames are in Portuguese. Could you check if the file being scanned when it crashed contains any of these characters?

ı (Turkish dotless i) → I
ß (German eszett)
fi fl (ligatures)
Or any accented characters that might behave unexpectedly
To help confirm this bug, could you:

Share the exact filename that was being processed when it crashed (check the logs right before the panic)
Or try temporarily renaming files with unusual Unicode characters to ASCII-only names and see if the scan completes
If we can identify the specific character causing this, I can submit a PR to fix the byte-length handling in the IsFsPathCaseSensitive function. The fix would be straightforward - the code needs to handle the case where the flipped string has a different byte length than the original.

1 Like
3

BTW I also use unRAID and my cache drives are btrfs and I’ve never had this issue but my filenames are likely all ASCII

4

Thank for the second look!

It is hard to determine which file is the cause of the issue because of the way stash terminates. You get a few log lines above that may or may not be related. With that said, I was able to create a minimal unit test that seems to panic with the same error.

if you put the following into pkg/fsutil/fs_test.go:

package fsutil

import (
	"os"
	"path/filepath"
	"testing"
)

func TestIsFsPathCaseSensitive_UnicodeByteLength(t *testing.T) {
	// Ⱥ (U+023A) is 2 bytes in UTF-8
	// Its lowercase ⱥ (U+2C65) is 3 bytes in UTF-8
	// This causes index out of range when the code tries to copy the longer
	// flipped bytes into the original-length byte slice

	dir := t.TempDir()
	path := filepath.Join(dir, "Ⱥtest")

	// Create the directory so os.Stat succeeds
	if err := os.Mkdir(path, 0755); err != nil {
		t.Fatal(err)
	}

	// This will panic: index out of range
	_, _ = IsFsPathCaseSensitive(path)
}

and execute the command

go test ./pkg/fsutil/... -run TestIsFsPathCaseSensitive -v

It should recreate the error

5

If you create a folder named “Ⱥtest123” in your scan directory, it will crash, regardless of the filesystem.

6

Great! So we at least know how to get you running, and confirmed that you don’t have to make any drastic changes to your system. I’ll open a PR on Stash for the bugfix!

1 Like
7

It only seems to crash if the first character of the directory is one of the Unicode special cases, so I just need to scan my files for those and rename them.

Thank you @carrotwaxr !

8

I created a new ticket so we don’t lose track of this If you create a folder named Ⱥtest123 in your scan directory, stash will crash · Issue #6571 · stashapp/stash · GitHub

1 Like