Unsafe pointer arithmetic #30

pztrn · 2020-03-03T10:42:54Z

I've compiled application with -race and it crashed right before showing up GUI.

fatal error: checkptr: unsafe pointer arithmetic

goroutine 1 [running, locked to thread]:
runtime.throw(0xce6324, 0x23)
        /usr/lib/go/src/runtime/panic.go:1112 +0x72 fp=0xc00011fa18 sp=0xc00011f9e8 pc=0x483d12
runtime.checkptrArithmetic(0x1, 0x0, 0x0, 0x0)
        /usr/lib/go/src/runtime/checkptr.go:24 +0xce fp=0xc00011fa48 sp=0xc00011fa18 pc=0x456fde
github.com/AllenDang/giu/imgui.TextureID.handle(...)
        /home/pztrn/projects/go/pkg/mod/github.com/!allen!dang/[email protected]/imgui/TextureID.go:24
github.com/AllenDang/giu/imgui.FontAtlas.SetTextureID.func1(0x27280e0, 0x1)
        /home/pztrn/projects/go/pkg/mod/github.com/!allen!dang/[email protected]/imgui/FontAtlas.go:174 +0x78 fp=0xc00011fa88 sp=0xc00011fa48 pc=0xa3c3c8
github.com/AllenDang/giu/imgui.FontAtlas.SetTextureID(0x27280e0, 0x1)
        /home/pztrn/projects/go/pkg/mod/github.com/!allen!dang/[email protected]/imgui/FontAtlas.go:174 +0x43 fp=0xc00011faa8 sp=0xc00011fa88 pc=0xa35683
github.com/AllenDang/giu/imgui.(*OpenGL3).createFontsTexture(0xc000074230)
        /home/pztrn/projects/go/pkg/mod/github.com/!allen!dang/[email protected]/imgui/RendererOpenGL3.go:338 +0x3e5 fp=0xc00011fb50 sp=0xc00011faa8 pc=0xa289f5
github.com/AllenDang/giu/imgui.(*OpenGL3).createDeviceObjects(0xc000074230)
        /home/pztrn/projects/go/pkg/mod/github.com/!allen!dang/[email protected]/imgui/RendererOpenGL3.go:292 +0xd26 fp=0xc00011fcc8 sp=0xc00011fb50 pc=0xa28256
github.com/AllenDang/giu/imgui.NewOpenGL3(0x2724368, 0x3fe00000, 0xb, 0x258, 0x1f4)
        /home/pztrn/projects/go/pkg/mod/github.com/!allen!dang/[email protected]/imgui/RendererOpenGL3.go:46 +0x1f5 fp=0xc00011fd50 sp=0xc00011fcc8 pc=0xa25485
github.com/AllenDang/giu.NewMasterWindowWithBgColor(0xcd52c1, 0xb, 0x258, 0x1f4, 0x1, 0xc00011fec0, 0x0, 0x7fd2ff3d8108)
        /home/pztrn/projects/go/pkg/mod/github.com/!allen!dang/[email protected]/MasterWindow.go:54 +0x263 fp=0xc00011fe30 sp=0xc00011fd50 pc=0xa53723
github.com/AllenDang/giu.NewMasterWindow(...)
        /home/pztrn/projects/go/pkg/mod/github.com/!allen!dang/[email protected]/MasterWindow.go:25

The text was updated successfully, but these errors were encountered:

AllenDang · 2020-03-04T02:37:28Z

It's a wrapper for a C pointer. I need to dig a little bit more about what -race does. BTW, it works fine in normal mode.

pztrn · 2020-03-04T07:02:37Z

Yep, I agree, but this will prevent running application with -race for race detection which is not good IMO.

AllenDang · 2020-03-04T07:54:10Z

@pztrn Yes, you got the point. I will dig it out.

AllenDang · 2020-03-07T06:13:12Z

This issue caused by converting uintptr to a C void* pointer. Anyone knows how to avoid this crash?

ryn1x · 2020-06-18T18:55:44Z

I am getting this same error. This prevents me from using the -race tool. Seems like a pretty big issues since there is a lot of concurrency going on in a typical GUI application and -race is really needed.

AllenDang · 2020-06-19T01:27:20Z

@ryn1x I'll take a look on this deeply this time. This is truly a big issue.

yarcat · 2020-08-12T20:48:14Z

The trick here is that there should be no unsafe.Pointer. All void* should be replaced with uintptr_t from <stdint.h> (or <cstdint>). If uintptr -to- void* conversion is required, it should be done on C side, not on Go.

Check this example commit, which allows to bypass first of the failures demonstrated by using -race option passed to go build/run.

It's quite tedious and non-rewarding work. But I'll do my best to help with it.

UPD: Forgot to mention, that I was trying to run go run -race ./examples/helloworld.

yarcat · 2020-08-12T22:30:06Z

Unfortunately they also have this in go-gl which makes it harder to fix as the rabbit hole is much deeper than I hoped.

AllenDang · 2020-08-13T02:24:31Z

@yarcat Yeah, I met the same upstream problem last time when I try to fix this.

kettek · 2020-10-07T19:47:56Z

To note, the fork @ https://github.com/neclepsio/gl has some variant function calls that, afaik, should resolve problems stemming from unsafe.Pointer use. I've experimentally tried using it (along with changing some of the imgui C interface) and it seemed to fix the pointer arithmetic problems.

AllenDang · 2020-10-08T06:51:46Z

@kettek Wow! Can you make a PR?

kettek · 2020-10-08T21:51:43Z

Sure. It ended up being part of my attempts to do per-texture filtering, so I'll separate it from that first.

runrc · 2020-11-04T14:43:53Z

Unfortunately this issue is a bit of show stopper for a concurrent GIU application, where using -race to catch data race issue is very important. Will this be resolved soon?

AllenDang · 2020-11-05T02:58:18Z

@ravicheema Cannot promise when, but I'm keep trying to fix it everyday.

kettek · 2020-11-06T22:08:09Z

I'll attempt to make a PR this weekend integrating the changes I had experimented with last month.

kettek · 2020-11-10T00:32:40Z

See #83

There are still issues with actual race conditions but this PR fixes the unsafe pointer arithmetic problem.

runrc · 2020-11-11T14:51:19Z

WORK AROUND - Go +1.14 has added -d=checkptr which adds instrumentation to check that Go code is following unsafe.Pointer safety rules when -race is specified. This can be disabled with gcflags=all=-d=checkptr=0

Use the following to perform data race condition checks and disable unsafe.Pointer safety rules,
go run -race -gcflags=all=-d=checkptr=0 .

Not ideal but it is a work around.

dertseha · 2021-04-30T19:41:19Z

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 giu 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.

Also, as the maintainer of imgui-go, I can report that the original issue about TextureID has also long been fixed.

kettek · 2021-04-30T23:47:14Z

Great to hear! I will rework the changes in PR #83, as that used a fork of go-gl/gl that implemented WithOffset, to use the updated go-gl/gl version as well as to reintegrate imgui-go's TextureID fixes.

Thanks for the update!

AllenDang · 2021-05-06T03:19:49Z

@dertseha Wow! This is a great news! @kettek Thanks for your great work! Looking forward for your PR.

gucio321 · 2021-10-05T16:45:00Z

@AllenDang it seems like upstream imgui-go doesn't have this issue anymore. I tried to run inkyblackness/imgui-go-examples example and it went clean.

AllenDang · 2021-10-08T09:02:48Z

@gucio321 I'll check it out and fix it soon.

runrc · 2022-01-31T11:17:36Z

@AllenDang and @gucio321
Any updates on this issue? This is an important issue for multiple-threaded applications.

gucio321 · 2022-03-22T08:45:34Z

well so like I said any example from inkyblackness/imgui-g-examples works well with -race so i suppose that @AllenDang needs to change something inside of AllenDang/imgui-go however idk what is the point there.

AllenDang · 2022-03-22T10:48:34Z

@gucio321 Yes, it's the root cause. I'm thinking about to use cimgui (as it is auto-generated and easy to sync the changes from imgui) to recreate the binding, might need more time to evaluate.
And sorry for the delay, :P

AllenDang · 2022-03-22T11:48:09Z

@pztrn @gucio321 @runrc I got it fixed, finally...
@dertseha Thanks for your code, they guide me step by step to right point.

AllenDang added the help wanted Extra attention is needed label Mar 7, 2020

kettek mentioned this issue Oct 6, 2020

Implement min/mag texture filtering #76

Merged

gucio321 mentioned this issue Feb 25, 2022

Using -race flag throws runtime checkptr errors #464

Closed

AllenDang added a commit that referenced this issue Mar 22, 2022

Solve #30

106202c

AllenDang closed this as completed Mar 22, 2022

gucio321 mentioned this issue Dec 12, 2022

data race AllenDang/cimgui-go#58

Closed

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Unsafe pointer arithmetic #30

Unsafe pointer arithmetic #30

pztrn commented Mar 3, 2020

AllenDang commented Mar 4, 2020

pztrn commented Mar 4, 2020

AllenDang commented Mar 4, 2020

AllenDang commented Mar 7, 2020

ryn1x commented Jun 18, 2020

AllenDang commented Jun 19, 2020

yarcat commented Aug 12, 2020 •

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yarcat commented Aug 12, 2020

AllenDang commented Aug 13, 2020

kettek commented Oct 7, 2020 •

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AllenDang commented Oct 8, 2020

kettek commented Oct 8, 2020

runrc commented Nov 4, 2020

AllenDang commented Nov 5, 2020

kettek commented Nov 6, 2020

kettek commented Nov 10, 2020

runrc commented Nov 11, 2020 •

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dertseha commented Apr 30, 2021

kettek commented Apr 30, 2021

AllenDang commented May 6, 2021

gucio321 commented Oct 5, 2021 •

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AllenDang commented Oct 8, 2021

runrc commented Jan 31, 2022 •

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gucio321 commented Mar 22, 2022

AllenDang commented Mar 22, 2022

AllenDang commented Mar 22, 2022

Unsafe pointer arithmetic #30

Unsafe pointer arithmetic #30

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pztrn commented Mar 3, 2020

AllenDang commented Mar 4, 2020

pztrn commented Mar 4, 2020

AllenDang commented Mar 4, 2020

AllenDang commented Mar 7, 2020

ryn1x commented Jun 18, 2020

AllenDang commented Jun 19, 2020

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yarcat commented Aug 12, 2020

AllenDang commented Aug 13, 2020

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AllenDang commented Oct 8, 2020

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runrc commented Nov 4, 2020

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dertseha commented Apr 30, 2021

kettek commented Apr 30, 2021

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runrc commented Jan 31, 2022 • edited Loading

gucio321 commented Mar 22, 2022

AllenDang commented Mar 22, 2022

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yarcat commented Aug 12, 2020 •

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kettek commented Oct 7, 2020 •

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runrc commented Nov 11, 2020 •

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runrc commented Jan 31, 2022 •

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