c - Segfault on `mkl_malloc`

Question

上下文

我想用英特尔的MKL库创建一个数组，然后用它做各种事情。但是，它在mkl_malloc上出错了。

问题

我正在尝试运行以下程序。在运行它时，我在指定的行得到一个segfault。问题出在mkl_malloc上。我能做些什么来解决这个问题？发生了什么事？

#include "mkl_types.h"
#include "mkl_spblas.h"
#include <stddef.h>  // For NULL
#include <stdio.h>

// Find reason for segfault
int main() {
    MKL_INT m=2000, k=1000;
    double  *A_dense;
    // Allocate memory to matrix
    A_dense = (double *)mkl_malloc( m*k*sizeof( double ), 128);  // Fails here.
    if (A_dense == NULL) {
        printf("ERROR: Can't allocate memory for matrices. Aborting... nn");
        mkl_free(A_dense);
        return 1;
    }
    mkl_free(A_dense);
    return 0;
}

编译使用：

 $ export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/opt/intel/mkl/lib/intel65
 $ gcc -m64 -I/opt/intel/mkl/include -L/opt/intel/mkl/lib/intel64 -lmkl_rt -lpthread -lm test_alloc.c -o test
test
test_alloc.c: In function 'main':
test_alloc.c:13:15: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]

我用valgrind得到的输出是这样的：

$ valgrind --leak-check=full ./test
==69680== Memcheck, a memory error detector
==69680== Copyright (C) 2002-2011, and GNU GPL'd, by Julian Seward et al.
==69680== Using Valgrind-3.7.0 and LibVEX; rerun with -h for copyright info
==69680== Command: ./test
==69680== 
==69680== Invalid read of size 8
==69680==    at 0x868D1D1: MKL_MALLOC (in /opt/intel/composerxe-2011.5.220/mkl/lib/intel64/libmkl_intel_lp64.so)
==69680==    by 0x4F56B1C: MKL_MALLOC (in /opt/intel/composerxe-2011.5.220/mkl/lib/intel64/libmkl_rt.so)
==69680==    by 0x4006B0: main (in /export/home/myuser/devel/part_distances/lib/test)
==69680==  Address 0xf42400 is not stack'd, malloc'd or (recently) free'd
==69680== 
==69680== 
==69680== Process terminating with default action of signal 11 (SIGSEGV)
==69680==  Access not within mapped region at address 0xF42400
==69680==    at 0x868D1D1: MKL_MALLOC (in /opt/intel/composerxe-2011.5.220/mkl/lib/intel64/libmkl_intel_lp64.so)
==69680==    by 0x4F56B1C: MKL_MALLOC (in /opt/intel/composerxe-2011.5.220/mkl/lib/intel64/libmkl_rt.so)
==69680==    by 0x4006B0: main (in /export/home/myuser/devel/part_distances/lib/test)
==69680==  If you believe this happened as a result of a stack
==69680==  overflow in your program's main thread (unlikely but
==69680==  possible), you can try to increase the size of the
==69680==  main thread stack using the --main-stacksize= flag.
==69680==  The main thread stack size used in this run was 8388608.
==69680== 
==69680== HEAP SUMMARY:
==69680==     in use at exit: 4,603 bytes in 19 blocks
==69680==   total heap usage: 19 allocs, 0 frees, 4,603 bytes allocated
==69680== 
==69680== LEAK SUMMARY:
==69680==    definitely lost: 0 bytes in 0 blocks
==69680==    indirectly lost: 0 bytes in 0 blocks
==69680==      possibly lost: 0 bytes in 0 blocks
==69680==    still reachable: 4,603 bytes in 19 blocks
==69680==         suppressed: 0 bytes in 0 blocks
==69680== Reachable blocks (those to which a pointer was found) are not shown.
==69680== To see them, rerun with: --leak-check=full --show-reachable=yes
==69680== 
==69680== For counts of detected and suppressed errors, rerun with: -v
==69680== ERROR SUMMARY: 1 errors from 1 contexts (suppressed: 4 from 4)
Segmentation fault

备选方案

我使用单一动态链接(SDL(，因为我无法使静态链接工作。

Answer 1

文档建议包括mkl.h。

所以改变：

#include "mkl_types.h"
#include "mkl_spblas.h"

至

#include "mkl.h"

Answer 2

您收到一个可怕的警告：

test_alloc.c:13:15: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]

我假设这是来自调用mkl_malloc():的代码行

A_dense = (double *)mkl_malloc( m*k*sizeof( double ), 128);

这意味着您丢失了标头，否则这里就不会有"整数"。

此外，您永远不应该像我之前在本网站上提到的那样，在C中投射void *。