What does Mprotect remapping failed mean and how do I fix it?

Hey guys!

I'm stumped with an error I found and from my searches, only a few have also received it a long time ago and I'm not quite sure if / how a solution was achieved.

The error I'm getting in xcode is

Code (csharp):

1. Mprotect failed at 0xed50000 (length 212992) with errno 12
2. Mprotect remapping failed

The game works fine in the editor and all other platforms. This error is iOS specific and happens every session that goes past the login process (loads another scene) for > 10 seconds. The exact time is inconsistent.
I say inconsistently because it doesn't seem to happen right after an interaction. My game does download data and images so my hunch (and a lousy hunch at that) is threading / wait time is the cause of the inconsistently.

Here's some of my search results

• http://forum.unity3d.com/threads/mprotect-failed-at-0x51fa000.15858/
  • this is from all the way back from 2008 and it looked like it was a hotfixed by Unity
• http://forum.unity3d.com/threads/mprotect-remapping-failed.15443/
  • this is more of the same but a Unity dev did mention:
    This is a little embarrassing since I'm a self taught Unity user but what exactly does that mean and can I apply it to my problem?

My system info
Currently on Unity 5.3 but has been happening since 5.2
Xcode is version 7.2 but has been happening since 7.0 I think
My game is 2d, it uses NGUI, it downloads data and images from the internet.

Thank you so much for your read and time. Hope you can help!

 

looks like it also is giving out the error code

Code (CSharp):

1. Using Unity SDK v7.2.2
2. (Filename: /Users/builduser/buildslave/unity/build/artifacts/generated/common/runtime/UnityEngineDebugBindings.gen.cpp Line: 37)
3.  
4. Using Unity SDK v7.2.2 with FBiOSSDK/4.7.0
5. (Filename: /Users/builduser/buildslave/unity/build/artifacts/generated/common/runtime/UnityEngineDebugBindings.gen.cpp Line: 37)
6.  
7. Mprotect failed at 0x416f8000 (length 4751360) with errno 12
8. Mprotect remapping failed
9. (lldb)

the xcode window above is displaying

Code (CSharp):

1. GIFingAround`::Texture2D_CUSTOM_GetPixels():
2.     0x21e9bf8 <+0>:   push   {r4, r5, r6, r7, lr}
3.     0x21e9bfc <+4>:   add    r7, sp, #12
4.     0x21e9c00 <+8>:   push   {r8, r10, r11}
5.     0x21e9c04 <+12>:  sub    sp, sp, #20
6.     0x21e9c08 <+16>:  mov    r5, r0
7.     0x21e9c0c <+20>:  cmp    r5, #0
8.     0x21e9c10 <+24>:  ldrne  r0, [r5, #0xc]
9.     0x21e9c14 <+28>:  mov    r11, r3
10.     0x21e9c18 <+32>:  cmpne  r0, #0
11.     0x21e9c1c <+36>:  beq    0x21e9cd0                 ; <+216> [inlined] GetReference at ScriptingObjectOfType.h:105
12.     0x21e9c20 <+40>:  ldr    r8, [r7, #0x8]
13.     0x21e9c24 <+44>:  mov    r10, r1
14.     0x21e9c28 <+48>:  ldrb   r1, [r0, #0x6b]
15.     0x21e9c2c <+52>:  str    r2, [sp, #0x10]
16.     0x21e9c30 <+56>:  cmp    r1, #0
17.     0x21e9c34 <+60>:  bne    0x21e9c58                 ; <+96> at TextureBindings.gen.cpp:413
18.     0x21e9c38 <+64>:  ldr    r1, [r0]
19.     0x21e9c3c <+68>:  ldr    r1, [r1, #0x20]
20.     0x21e9c40 <+72>:  blx    r1
21.     0x21e9c44 <+76>:  mov    r1, r0
22.     0x21e9c48 <+80>:  movw   r0, #0x1772
23.     0x21e9c4c <+84>:  movt   r0, #0x6c
24.     0x21e9c50 <+88>:  add    r0, pc, r0
25.     0x21e9c54 <+92>:  bl     0x1d98734                 ; ::RaiseMonoException() at Scripting_Mono.cpp:87
26.     0x21e9c58 <+96>:  mul    r4, r8, r11
27.     0x21e9c5c <+100>: bl     0x1eced88                 ; ::GetCoreScriptingClasses() at CoreScriptingClasses.cpp:274
28.     0x21e9c60 <+104>: ldr    r0, [r0, #0x94]
29.     0x21e9c64 <+108>: mov    r1, #16
30.     0x21e9c68 <+112>: mov    r2, r4
31.     0x21e9c6c <+116>: bl     0x1d99654                 ; ::scripting_array_new() at ScriptingBackendApi_Mono.cpp:543
32.     0x21e9c70 <+120>: mov    r6, r0
33.     0x21e9c74 <+124>: mov    r1, #0
34.     0x21e9c78 <+128>: mov    r2, #16
35.     0x21e9c7c <+132>: bl     0x1d99644                 ; ::scripting_array_element_ptr() at ScriptingBackendApi_Mono.cpp:533
36.     0x21e9c80 <+136>: mov    r4, r0
37.     0x21e9c84 <+140>: ldr    r0, [r5, #0xc]
38.     0x21e9c88 <+144>: cmp    r0, #0
39.     0x21e9c8c <+148>: bne    0x21e9c9c                 ; <+164> at ScriptingObjectOfType.h:32
40.     0x21e9c90 <+152>: mov    r0, r5
41.     0x21e9c94 <+156>: bl     0x1d988e8                 ; ::RaiseNullExceptionObject() at Scripting_Mono.cpp:202
42.     0x21e9c98 <+160>: mov    r0, #0
43.     0x21e9c9c <+164>: ldr    r1, [r7, #0xc]
44.     0x21e9ca0 <+168>: mov    r3, r11
45.     0x21e9ca4 <+172>: str    r8, [sp]
46.     0x21e9ca8 <+176>: stmib  sp, {r1, r4}
47.     0x21e9cac <+180>: mov    r1, #0
48.     0x21e9cb0 <+184>: ldr    r2, [sp, #0x10]
49.     0x21e9cb4 <+188>: str    r1, [sp, #0xc]
50.     0x21e9cb8 <+192>: mov    r1, r10
51.     0x21e9cbc <+196>: bl     0x1dd0d34                 ; ::GetPixels() at Texture2D.cpp:1215
52.     0x21e9cc0 <+200>: mov    r0, r6
53.     0x21e9cc4 <+204>: sub    sp, r7, #24
54.     0x21e9cc8 <+208>: pop    {r8, r10, r11}
55.     0x21e9ccc <+212>: pop    {r4, r5, r6, r7, pc}
56.     0x21e9cd0 <+216>: mov    r0, r5
57.     0x21e9cd4 <+220>: bl     0x1d988e8                 ; ::RaiseNullExceptionObject() at Scripting_Mono.cpp:202
58.  

I'm wondering if its an NGUI issue?

Someone else did have the issue as well so its not just me.

 

I am also having the same issue, with uploading 'large' files (tested on 10 - 20 MB files). Something wrong with the WWW class? I have tested on Unity 5.1 and 5.3

 

Have you found a solution/reported the bug via the editor?

 

Haven't found a solution yet and have't gotten the bug to happen in the editor either. It only happens on ios builds.

 

I think he meant report it via the bug reporter menu item in the editor. Is your project small enough that you feel like giving it to them, or can you reproduce the error with a smaller one?

Your hunch is possibly right, as mprotect() has to do with memory region protection. It could be a case of memory being write-protected when it shouldn't due to a race condition. It doesn't seem like something that is directly your fault either.

 

Oh ok I see. My project isn't small enough right now but I can work on reducing it to just the bare essentials and report it.

Well that's kind of a relief

I should also point out that when inspecting available memory in xcode on my device, my app is using like 25% of available memory leaving like 45% free (when you take into account background memory).

 

took me a while but I submitted the bug with my project. I'll update once I get the link.

 

how long does it usually take to get your bug into the public issue tracker?

 

Weekends are pretty random. It's happened, but it really depends on somebody receiving it and being really eager to fix it

 

Lol didn't expect it on the weekends. That makes sense though.

@PDZ, could you also submit a bug? Maybe we can find strength in numbers.

 

Yes it is 763225

 

just got an email!

 

Awesome - confirmation is the best, even if it's not fixed immediately

 

Can you please share a link to the bug report so we can view it/monitor updates?

 

Oh yay! Its on the public issue tracker now. Everyone plese vote!

https://issuetracker.unity3d.com/issues/ios-application-crashes-while-allocating-memory-for-texture