race detector: fatal error: checkptr: pointer arithmetic computed bad pointer value

[tehsphinx]

Describe the bug:

Starting an application with go run --race . crashes with the following error at startup:

fatal error: checkptr: pointer arithmetic computed bad pointer value

goroutine 40 [running, locked to thread]:
runtime.throw(0x4601533, 0x37)
/usr/local/go/src/runtime/panic.go:1116 +0x72 fp=0xc000629538 sp=0xc000629508 pc=0x403b9b2
runtime.checkptrArithmetic(0xc, 0x0, 0x0, 0x0)
/usr/local/go/src/runtime/checkptr.go:26 +0xd7 fp=0xc000629568 sp=0xc000629538 pc=0x400d1f7
github.com/go-gl/gl/v3.2-core/gl.PtrOffset(...)
/Users/user/go/pkg/mod/github.com/go-gl/gl@v0.0.0-20190320180904-bf2b1f2f34d7/v3.2-core/gl/conversions.go:55
fyne.io/fyne/v2/internal/painter/gl.(*glPainter).glCreateBuffer(0xc000606000, 0xc000026050, 0x14, 0x14, 0x0)
/Users/user/go/pkg/mod/fyne.io/fyne/v2@v2.0.0/internal/painter/gl/gl_core.go:219 +0x409 fp=0xc000629608 sp=0xc000629568 pc=0x43f2f29
fyne.io/fyne/v2/internal/painter/gl.(*glPainter).drawTextureWithDetails(0xc000606000, 0x46726c0, 0xc0002e42a0, 0xc0006296e8, 0x4140000041000000, 0x41a8000042ee0000, 0x43fa000044480000, 0x0, 0x3f800000)
/Users/user/go/pkg/mod/fyne.io/fyne/v2@v2.0.0/internal/painter/gl/draw.go:27 +0x152 fp=0xc000629668 sp=0xc000629608 pc=0x43ee272
fyne.io/fyne/v2/internal/painter/gl.(*glPainter).drawText(0xc000606000, 0xc0002e42a0, 0x4140000041000000, 0x43fa000044480000)
/Users/user/go/pkg/mod/fyne.io/fyne/v2@v2.0.0/internal/painter/gl/draw.go:78 +0x357 fp=0xc000629708 sp=0xc000629668 pc=0x43ef057
fyne.io/fyne/v2/internal/painter/gl.(*glPainter).drawObject(0xc000606000, 0x46726c0, 0xc0002e42a0, 0x4140000041000000, 0x43fa000044480000)
/Users/user/go/pkg/mod/fyne.io/fyne/v2@v2.0.0/internal/painter/gl/draw.go:97 +0x3d1 fp=0xc000629758 sp=0xc000629708 pc=0x43ef591
fyne.io/fyne/v2/internal/painter/gl.(*glPainter).Paint(0xc000606000, 0x46726c0, 0xc0002e42a0, 0x4140000041000000, 0x43fa000044480000)
/Users/user/go/pkg/mod/fyne.io/fyne/v2@v2.0.0/internal/painter/gl/painter.go:70 +0xab fp=0xc000629790 sp=0xc000629758 pc=0x43f392b
fyne.io/fyne/v2/internal/driver/glfw.(*glCanvas).paint.func1(0xc000622080, 0x4140000041000000)
/Users/user/go/pkg/mod/fyne.io/fyne/v2@v2.0.0/internal/driver/glfw/canvas.go:435 +0x138 fp=0xc000629818 sp=0xc000629790 pc=0x4451698
fyne.io/fyne/v2/internal/driver/glfw.(*glCanvas).walkTree.func1(0x46726c0, 0xc0002e42a0, 0x4140000041000000, 0x0, 0x4f0000004f000000, 0xc000629d00)
/Users/user/go/pkg/mod/fyne.io/fyne/v2@v2.0.0/internal/driver/glfw/canvas.go:516 +0x1e2 fp=0xc000629888 sp=0xc000629818 pc=0x4451e02
fyne.io/fyne/v2/internal/driver.walkObjectTree(0x46726c0, 0xc0002e42a0, 0x4080000040800000, 0x4672ba0, 0xc0001483f0, 0x4080000040800000, 0x0, 0x4f0000004f000000, 0xc000629cc8, 0xc000629ca0, ...)
/Users/user/go/pkg/mod/fyne.io/fyne/v2@v2.0.0/internal/driver/util.go:169 +0x593 fp=0xc000629948 sp=0xc000629888 pc=0x4277893
fyne.io/fyne/v2/internal/driver.walkObjectTree.func1(...)
/Users/user/go/pkg/mod/fyne.io/fyne/v2@v2.0.0/internal/driver/util.go:176
fyne.io/fyne/v2/internal/driver.walkObjectTree(0x4672ba0, 0xc0001483f0, 0x4080000040800000, 0x46723c0, 0xc00014c6c0, 0x4080000040800000, 0x0, 0x4f0000004f000000, 0xc000629cc8, 0xc000629ca0, ...)
/Users/user/go/pkg/mod/fyne.io/fyne/v2@v2.0.0/internal/driver/util.go:190 +0x4f0 fp=0xc000629a08 sp=0xc000629948 pc=0x42777f0
fyne.io/fyne/v2/internal/driver.walkObjectTree.func1(...)
/Users/user/go/pkg/mod/fyne.io/fyne/v2@v2.0.0/internal/driver/util.go:176
fyne.io/fyne/v2/internal/driver.walkObjectTree(0x46723c0, 0xc00014c6c0, 0x4080000040800000, 0x46723c0, 0xc00014cb00, 0x4080000040800000, 0x0, 0x4f0000004f000000, 0xc000629cc8, 0xc000629ca0, ...)
/Users/user/go/pkg/mod/fyne.io/fyne/v2@v2.0.0/internal/driver/util.go:190 +0x4f0 fp=0xc000629ac8 sp=0xc000629a08 pc=0x42777f0
fyne.io/fyne/v2/internal/driver.walkObjectTree.func1(...)
/Users/user/go/pkg/mod/fyne.io/fyne/v2@v2.0.0/internal/driver/util.go:176
fyne.io/fyne/v2/internal/driver.walkObjectTree(0x46723c0, 0xc00014cb00, 0x0, 0x0, 0x0, 0x0, 0x0, 0x4f0000004f000000, 0xc000629cc8, 0xc000629ca0, ...)
/Users/user/go/pkg/mod/fyne.io/fyne/v2@v2.0.0/internal/driver/util.go:190 +0x4f0 fp=0xc000629b88 sp=0xc000629ac8 pc=0x42777f0
fyne.io/fyne/v2/internal/driver.WalkVisibleObjectTree(0x46723c0, 0xc00014cb00, 0xc000629cc8, 0xc000629ca0, 0xc0ffffffff)
/Users/user/go/pkg/mod/fyne.io/fyne/v2@v2.0.0/internal/driver/util.go:134 +0xa5 fp=0xc000629c00 sp=0xc000629b88 pc=0x42772c5
fyne.io/fyne/v2/internal/driver/glfw.(*glCanvas).walkTree(0xc000354000, 0xc00012edc0, 0xc000629d98, 0xc000629d80)
/Users/user/go/pkg/mod/fyne.io/fyne/v2@v2.0.0/internal/driver/glfw/canvas.go:537 +0x20b fp=0xc000629d00 sp=0xc000629c00 pc=0x443bf8b
fyne.io/fyne/v2/internal/driver/glfw.(*glCanvas).walkTrees(0xc000354000, 0xc000629d98, 0xc000629d80)
/Users/user/go/pkg/mod/fyne.io/fyne/v2@v2.0.0/internal/driver/glfw/canvas.go:544 +0x74 fp=0xc000629d50 sp=0xc000629d00 pc=0x443c054
fyne.io/fyne/v2/internal/driver/glfw.(*glCanvas).paint(0xc000354000, 0x43fa000044480000)
/Users/user/go/pkg/mod/fyne.io/fyne/v2@v2.0.0/internal/driver/glfw/canvas.go:449 +0x14e fp=0xc000629dc8 sp=0xc000629d50 pc=0x443bb4e
fyne.io/fyne/v2/internal/driver/glfw.(*gLDriver).repaintWindow.func1()
/Users/user/go/pkg/mod/fyne.io/fyne/v2@v2.0.0/internal/driver/glfw/loop.go:164 +0xb3 fp=0xc000629e18 sp=0xc000629dc8 pc=0x44529b3
fyne.io/fyne/v2/internal/driver/glfw.(*window).RunWithContext(0xc00017c1c0, 0xc0000a3e40)
/Users/user/go/pkg/mod/fyne.io/fyne/v2@v2.0.0/internal/driver/glfw/window.go:1181 +0x56 fp=0xc000629e30 sp=0xc000629e18 pc=0x444fff6
fyne.io/fyne/v2/internal/driver/glfw.(*gLDriver).repaintWindow(0xc0001003c0, 0xc00017c1c0)
/Users/user/go/pkg/mod/fyne.io/fyne/v2@v2.0.0/internal/driver/glfw/loop.go:155 +0x88 fp=0xc000629e68 sp=0xc000629e30 pc=0x443f1c8
fyne.io/fyne/v2/internal/driver/glfw.(*gLDriver).startDrawThread.func1(0xc0001003c0, 0xc0001023c0, 0xc000100410)
/Users/user/go/pkg/mod/fyne.io/fyne/v2@v2.0.0/internal/driver/glfw/loop.go:211 +0x357 fp=0xc000629fc8 sp=0xc000629e68 pc=0x4452df7
runtime.goexit()
/usr/local/go/src/runtime/asm_amd64.s:1374 +0x1 fp=0xc000629fd0 sp=0xc000629fc8 pc=0x4071ac1
created by fyne.io/fyne/v2/internal/driver/glfw.(*gLDriver).startDrawThread
/Users/user/go/pkg/mod/fyne.io/fyne/v2@v2.0.0/internal/driver/glfw/loop.go:182 +0xcb

Example code:

For now I assume it will crash with every application given that it crashes way down in the gl code. If this is not the case let me know and I will try to provide minimal reproducable code.

Device (please complete the following information):

• MacOS Big Sur 11.2.1
• go version go1.15.7 darwin/amd64
• fyne.io/fyne/v2 v2.0.0

[tehsphinx]

I just realize this is a dependency, so here the issue for it: go-gl/gl#124

[tehsphinx]

Also: go-gl/gl#80

[tehsphinx]

From go-gl issue on the subject:

using GODEBUG=cgocheck=0 can disable these checks but seems like kind of a hacky-workaround, especially if you need runtime pointer checks for other packages.

[andydotxyz]

Looks like an issue triggered by Go 1.14 pingcap/tidb#14972

[dertseha]

Hello there!
I bring greetings from go-gl/gl, where a PR ( go-gl/gl#135 ) has landed that allows to handle checkptr issues - for the most common GL calls.

For example, instead of calling gl.VertexAttribPointer() the code needs to call the newly available gl.VertexAttribPointerWithOffset() - Note the change in type of the last argument.

There are a few more overloads with WithOffset in their name. There might be more functions that need this treatment - see READMEs of go-gl/glow and go-gl/gl for more details on checkptr and overloads in case more function overloads are needed.

In general, any use of gl.PtrOffset() is discouraged - a future update has it marked as deprecated.

I have not reviewed the fyne code, my proposal is to remove any use of PtrOffset() and ensure direct use of uintptr type - and in case overloads are needed, use those or please report them missing.

[andydotxyz]

Thanks so much for your hints there @dertseha that worked well and this issue is now resolved :)

[andydotxyz]

This was resolved in 7af0d98, not sure why it was not linked to this issue