malloc works, cudaHostAlloc segfaults?
- by Mikhail
I am new to CUDA and I want to use cudaHostAlloc. I was able to isolate my problem to this following code. Using malloc for host allocation works, using cudaHostAlloc results in a segfault, possibly because the area allocated is invalid? When I dump the pointer in both cases it is not null, so cudaHostAlloc returns something...
works
in_h = (int*) malloc(length*sizeof(int)); //works
for (int i = 0;i<length;i++)
in_h[i]=2;
doesn't work
cudaHostAlloc((void**)&in_h,length*sizeof(int),cudaHostAllocDefault);
for (int i = 0;i<length;i++)
in_h[i]=2; //segfaults
Standalone Code
#include <stdio.h>
void checkDevice()
{
cudaDeviceProp info;
int deviceName;
cudaGetDevice(&deviceName);
cudaGetDeviceProperties(&info,deviceName);
if (!info.deviceOverlap)
{
printf("Compute device can't use streams and should be discared.");
exit(EXIT_FAILURE);
}
}
int main()
{
checkDevice();
int *in_h;
const int length = 10000;
cudaHostAlloc((void**)&in_h,length*sizeof(int),cudaHostAllocDefault);
printf("segfault comming %d\n",in_h);
for (int i = 0;i<length;i++)
{
in_h[i]=2;
}
free(in_h);
return EXIT_SUCCESS;
}
~
Invocation
[id129]$ nvcc fun.cu
[id129]$ ./a.out
segfault comming 327641824
Segmentation fault (core dumped)
Details
Program is run in interactive mode on a cluster. I was told that an invocation of the program from the compute node pushes it to the cluster. Have not had any trouble with other home made toy cuda codes.
