cuda-memcheck error: Address is out of bounds.

Accelerated Computing CUDA CUDA Programming and Performance
1

In my machine, CUDA Driver Version: 4.2 CUDA Capability Major/Minor version number: 2.1

I used cuda-memcheck to detect kernel function error and it shows:

CUDA error at gbh.cu:266: unspecified launch failure
========= Invalid global read of size 8
========= at 0x00003068 in edges.h:110:gb
========= by thread (0,0,0) in block (0,0,0)
========= Address 0x00d745f0 is out of bounds

========= Invalid global read of size 8
========= at 0x00003068 in edges.h:110:gb
========= by thread (0,0,0) in block (1,0,0)
========= Address 0x00d74690 is out of bounds

========= Invalid global read of size 8
========= at 0x00003068 in edges.h:110:gb
========= by thread (0,0,0) in block (2,0,0)
========= Address 0x00d74730 is out of bounds

========= Invalid global read of size 8
========= at 0x00003068 in edges.h:110:gb
========= by thread (0,0,0) in block (3,0,0)
========= Address 0x00d747d0 is out of bounds

========= ERROR SUMMARY: 4 errors

But I can access the address with printf before executing the kernel function like this:

-----------------The first smooth_r address is 0xd745f0
-----------------The second smooth_r address is 0xd74690
-----------------The third smooth_r address is 0xd74730
-----------------The fourth smooth_r address is 0xd747d0

It seems contradictable to the cuda-memcheck error.

What’s the reason?

Thanks for your time.

2

Hello,

My 2 cents on this is that the program is accessing out of bonds, but it does not mean it will crash when you do a normal run (aka no debug). It will just use whatever is written at that address. Different architecture will behave differently, on some your program will crash while on others it will continue running. If you have a very large matrix I am sure it will crash on every architecture. I suggest you trust the cuda-memcheck and address your problem, otherwise you might have problems later.
The cuda-memcheck is just signalling that you defined some array of size N and your index i is >= N.

3

Some more context is needed here. Can you post your entire application?