valgrind"未初始化的值"警告ATLAS多线程BLAS例程中的误报吗？

我正在使用ATLAS进行LAPACK和多线程BLAS例程,并且注意到当我的矩阵足够大以致ATLAS使用BLAS的多线程版本时,我从Valgrind得到初始化错误.这是我的代码中的一个最小示例:

#include 
#include 

extern void dgetrf_(int *, int *, double *, int *, int *, int *);
extern void dgetri_(int *, double *, int *, int *, double *, int *, int *);
extern void dgemm_(char *, char *, int *, int *, int *, double *, double *, int *, double *, int *, double *, double *, int *);

int main(void)
{
    double *m1,*m2,*work,*temp;
    int dim = 576;
    int i,j,info;
    int lwork = dim * dim;
    int *ipiv;
    char transA = 'N';
    char transB = 'N';
    double alpha = 1.0;
    double beta = 0.0;

    m1 = malloc(dim*dim*sizeof(double));
    m2 = malloc(dim*dim*sizeof(double));
    temp = malloc(dim*dim*sizeof(double));
    ipiv = malloc(dim*sizeof(int));
    work = malloc(lwork*sizeof(double));

    for(i=0; i

(注意:我已经检查过以确保矩阵不是单数,而它们不是.)

我编译程序:

gcc -Wall -DATLAS -m64 -g -c fermi.c
gcc -o fermi fermi.o -L/usr/lib64/atlas/ -lm -ltatlas


并运行valgrind:

valgrind --leak-check=yes ./fermi


当我这样做时,当遇到dgetrf_和dgetri_的第二个实例时,我从11个上下文中获得193个错误"条件跳转或移动取决于未初始化的值".

==24999== Memcheck, a memory error detector
==24999== Copyright (C) 2002-2015, and GNU GPL'd, by Julian Seward et al.
==24999== Using Valgrind-3.12.0 and LibVEX; rerun with -h for copyright info
==24999== Command: ./fermi
==24999== 
==24999== Conditional jump or move depends on uninitialised value(s)
==24999==    at 0x524C62B: ??? (in /usr/lib64/atlas/libtatlas.so.3.10)
==24999==    by 0x51C29E3: ATL_dgetf2 (in /usr/lib64/atlas/libtatlas.so.3.10)
==24999==    by 0x51CD2BF: ATL_dtgetrfC (in /usr/lib64/atlas/libtatlas.so.3.10)
==24999==    by 0x51CD2BF: ATL_dtgetrfC (in /usr/lib64/atlas/libtatlas.so.3.10)
==24999==    by 0x51CD2BF: ATL_dtgetrfC (in /usr/lib64/atlas/libtatlas.so.3.10)
==24999==    by 0x51CD2BF: ATL_dtgetrfC (in /usr/lib64/atlas/libtatlas.so.3.10)
==24999==    by 0x520F538: atl_f77wrap_dgetrf_ (in /usr/lib64/atlas/libtatlas.so.3.10)
==24999==    by 0x5210416: dgetrf_ (in /usr/lib64/atlas/libtatlas.so.3.10)
==24999==    by 0x400A97: main (fermi.c:52)
==24999== 
==24999== Conditional jump or move depends on uninitialised value(s)
==24999==    at 0x524C66A: ??? (in /usr/lib64/atlas/libtatlas.so.3.10)
==24999==    by 0x51C29E3: ATL_dgetf2 (in /usr/lib64/atlas/libtatlas.so.3.10)
==24999==    by 0x51CD2BF: ATL_dtgetrfC (in /usr/lib64/atlas/libtatlas.so.3.10)
==24999==    by 0x51CD2BF: ATL_dtgetrfC (in /usr/lib64/atlas/libtatlas.so.3.10)
==24999==    by 0x51CD2BF: ATL_dtgetrfC (in /usr/lib64/atlas/libtatlas.so.3.10)
==24999==    by 0x51CD2BF: ATL_dtgetrfC (in /usr/lib64/atlas/libtatlas.so.3.10)
==24999==    by 0x520F538: atl_f77wrap_dgetrf_ (in /usr/lib64/atlas/libtatlas.so.3.10)
==24999==    by 0x5210416: dgetrf_ (in /usr/lib64/atlas/libtatlas.so.3.10)
==24999==    by 0x400A97: main (fermi.c:52)
==24999== 
==24999== Conditional jump or move depends on uninitialised value(s)
==24999==    at 0x524C6BE: ??? (in /usr/lib64/atlas/libtatlas.so.3.10)
==24999==    by 0x51C29E3: ATL_dgetf2 (in /usr/lib64/atlas/libtatlas.so.3.10)
==24999==    by 0x51CD2BF: ATL_dtgetrfC (in /usr/lib64/atlas/libtatlas.so.3.10)
==24999==    by 0x51CD2BF: ATL_dtgetrfC (in /usr/lib64/atlas/libtatlas.so.3.10)
==24999==    by 0x51CD2BF: ATL_dtgetrfC (in /usr/lib64/atlas/libtatlas.so.3.10)
==24999==    by 0x51CD2BF: ATL_dtgetrfC (in /usr/lib64/atlas/libtatlas.so.3.10)
==24999==    by 0x520F538: atl_f77wrap_dgetrf_ (in /usr/lib64/atlas/libtatlas.so.3.10)
==24999==    by 0x5210416: dgetrf_ (in /usr/lib64/atlas/libtatlas.so.3.10)
==24999==    by 0x400A97: main (fermi.c:52)
==24999== 
==24999== Conditional jump or move depends on uninitialised value(s)
==24999==    at 0x51C2A0B: ATL_dgetf2 (in /usr/lib64/atlas/libtatlas.so.3.10)
==24999==    by 0x51CD2BF: ATL_dtgetrfC (in /usr/lib64/atlas/libtatlas.so.3.10)
==24999==    by 0x51CD2BF: ATL_dtgetrfC (in /usr/lib64/atlas/libtatlas.so.3.10)
==24999==    by 0x51CD2BF: ATL_dtgetrfC (in /usr/lib64/atlas/libtatlas.so.3.10)
==24999==    by 0x51CD2BF: ATL_dtgetrfC (in /usr/lib64/atlas/libtatlas.so.3.10)
==24999==    by 0x520F538: atl_f77wrap_dgetrf_ (in /usr/lib64/atlas/libtatlas.so.3.10)
==24999==    by 0x5210416: dgetrf_ (in /usr/lib64/atlas/libtatlas.so.3.10)
==24999==    by 0x400A97: main (fermi.c:52)
==24999== 
==24999== Conditional jump or move depends on uninitialised value(s)
==24999==    at 0x51C2A0D: ATL_dgetf2 (in /usr/lib64/atlas/libtatlas.so.3.10)
==24999==    by 0x51CD2BF: ATL_dtgetrfC (in /usr/lib64/atlas/libtatlas.so.3.10)
==24999==    by 0x51CD2BF: ATL_dtgetrfC (in /usr/lib64/atlas/libtatlas.so.3.10)
==24999==    by 0x51CD2BF: ATL_dtgetrfC (in /usr/lib64/atlas/libtatlas.so.3.10)
==24999==    by 0x51CD2BF: ATL_dtgetrfC (in /usr/lib64/atlas/libtatlas.so.3.10)
==24999==    by 0x520F538: atl_f77wrap_dgetrf_ (in /usr/lib64/atlas/libtatlas.so.3.10)
==24999==    by 0x5210416: dgetrf_ (in /usr/lib64/atlas/libtatlas.so.3.10)
==24999==    by 0x400A97: main (fermi.c:52)
==24999== 
==24999== Conditional jump or move depends on uninitialised value(s)
==24999==    at 0x51C2A4E: ATL_dgetf2 (in /usr/lib64/atlas/libtatlas.so.3.10)
==24999==    by 0x51CD2BF: ATL_dtgetrfC (in /usr/lib64/atlas/libtatlas.so.3.10)
==24999==    by 0x51CD2BF: ATL_dtgetrfC (in /usr/lib64/atlas/libtatlas.so.3.10)
==24999==    by 0x51CD2BF: ATL_dtgetrfC (in /usr/lib64/atlas/libtatlas.so.3.10)
==24999==    by 0x51CD2BF: ATL_dtgetrfC (in /usr/lib64/atlas/libtatlas.so.3.10)
==24999==    by 0x520F538: atl_f77wrap_dgetrf_ (in /usr/lib64/atlas/libtatlas.so.3.10)
==24999==    by 0x5210416: dgetrf_ (in /usr/lib64/atlas/libtatlas.so.3.10)
==24999==    by 0x400A97: main (fermi.c:52)
==24999== 
==24999== Conditional jump or move depends on uninitialised value(s)
==24999==    at 0x51C2A61: ATL_dgetf2 (in /usr/lib64/atlas/libtatlas.so.3.10)
==24999==    by 0x51CD2BF: ATL_dtgetrfC (in /usr/lib64/atlas/libtatlas.so.3.10)
==24999==    by 0x51CD2BF: ATL_dtgetrfC (in /usr/lib64/atlas/libtatlas.so.3.10)
==24999==    by 0x51CD2BF: ATL_dtgetrfC (in /usr/lib64/atlas/libtatlas.so.3.10)
==24999==    by 0x51CD2BF: ATL_dtgetrfC (in /usr/lib64/atlas/libtatlas.so.3.10)
==24999==    by 0x520F538: atl_f77wrap_dgetrf_ (in /usr/lib64/atlas/libtatlas.so.3.10)
==24999==    by 0x5210416: dgetrf_ (in /usr/lib64/atlas/libtatlas.so.3.10)
==24999==    by 0x400A97: main (fermi.c:52)
==24999== 
==24999== Conditional jump or move depends on uninitialised value(s)
==24999==    at 0x524C2D7: ATL_daxpy (in /usr/lib64/atlas/libtatlas.so.3.10)
==24999==    by 0x53426BB: ATL_dgerk_axpy (in /usr/lib64/atlas/libtatlas.so.3.10)
==24999==    by 0x51C2AC7: ATL_dgetf2 (in /usr/lib64/atlas/libtatlas.so.3.10)
==24999==    by 0x51CD2BF: ATL_dtgetrfC (in /usr/lib64/atlas/libtatlas.so.3.10)
==24999==    by 0x51CD2BF: ATL_dtgetrfC (in /usr/lib64/atlas/libtatlas.so.3.10)
==24999==    by 0x51CD2BF: ATL_dtgetrfC (in /usr/lib64/atlas/libtatlas.so.3.10)
==24999==    by 0x51CD2BF: ATL_dtgetrfC (in /usr/lib64/atlas/libtatlas.so.3.10)
==24999==    by 0x520F538: atl_f77wrap_dgetrf_ (in /usr/lib64/atlas/libtatlas.so.3.10)
==24999==    by 0x5210416: dgetrf_ (in /usr/lib64/atlas/libtatlas.so.3.10)
==24999==    by 0x400A97: main (fermi.c:52)
==24999== 
==24999== Conditional jump or move depends on uninitialised value(s)
==24999==    at 0x524C751: ??? (in /usr/lib64/atlas/libtatlas.so.3.10)
==24999==    by 0x51C29E3: ATL_dgetf2 (in /usr/lib64/atlas/libtatlas.so.3.10)
==24999==    by 0x51CD2BF: ATL_dtgetrfC (in /usr/lib64/atlas/libtatlas.so.3.10)
==24999==    by 0x51CD2BF: ATL_dtgetrfC (in /usr/lib64/atlas/libtatlas.so.3.10)
==24999==    by 0x51CD2BF: ATL_dtgetrfC (in /usr/lib64/atlas/libtatlas.so.3.10)
==24999==    by 0x51CD2BF: ATL_dtgetrfC (in /usr/lib64/atlas/libtatlas.so.3.10)
==24999==    by 0x520F538: atl_f77wrap_dgetrf_ (in /usr/lib64/atlas/libtatlas.so.3.10)
==24999==    by 0x5210416: dgetrf_ (in /usr/lib64/atlas/libtatlas.so.3.10)
==24999==    by 0x400A97: main (fermi.c:52)
==24999== 
==24999== Conditional jump or move depends on uninitialised value(s)
==24999==    at 0x51CD8E5: ATL_dtrtri (in /usr/lib64/atlas/libtatlas.so.3.10)
==24999==    by 0x51C2EC3: ATL_dgetriC (in /usr/lib64/atlas/libtatlas.so.3.10)
==24999==    by 0x520EFA5: atl_f77wrap_dgetri_ (in /usr/lib64/atlas/libtatlas.so.3.10)
==24999==    by 0x520F684: dgetri_ (in /usr/lib64/atlas/libtatlas.so.3.10)
==24999==    by 0x400AC0: main (fermi.c:53)
==24999== 
==24999== Conditional jump or move depends on uninitialised value(s)
==24999==    at 0x51CD8E7: ATL_dtrtri (in /usr/lib64/atlas/libtatlas.so.3.10)
==24999==    by 0x51C2EC3: ATL_dgetriC (in /usr/lib64/atlas/libtatlas.so.3.10)
==24999==    by 0x520EFA5: atl_f77wrap_dgetri_ (in /usr/lib64/atlas/libtatlas.so.3.10)
==24999==    by 0x520F684: dgetri_ (in /usr/lib64/atlas/libtatlas.so.3.10)
==24999==    by 0x400AC0: main (fermi.c:53)
==24999== 
==24999== 
==24999== HEAP SUMMARY:
==24999==     in use at exit: 0 bytes in 0 blocks
==24999==   total heap usage: 2,024 allocs, 2,024 frees, 54,831,424 bytes allocated
==24999== 
==24999== All heap blocks were freed -- no leaks are possible
==24999== 
==24999== For counts of detected and suppressed errors, rerun with: -v
==24999== Use --track-origins=yes to see where uninitialised values come from
==24999== ERROR SUMMARY: 193 errors from 11 contexts (suppressed: 0 from 0)


我发现了一些链接,表明这可能是来自图书馆工作方式的误报,尽管它们与我的上下文没有多大关系.

dgemm_中的内存泄漏

https://www.open-mpi.org/community/lists/users/2007/05/3192.php

所以我的问题是: valgrind是否给了我误报？


1> ks1322..：

  
valgrind给我误报了吗？


看起来没有.

--leak-check=yes你应该运行它而不是运行valgrind,--track-origins=yes以查看输出结束时valgrind建议的未初始化值的来源.这就是我所拥有的--track-origins=yes:

[ ~]$ valgrind --track-origins=yes ./a.out 
==17533== Memcheck, a memory error detector
==17533== Copyright (C) 2002-2015, and GNU GPL'd, by Julian Seward et al.
==17533== Using Valgrind-3.12.0 and LibVEX; rerun with -h for copyright info
==17533== Command: ./a.out
==17533== 
==17533== Conditional jump or move depends on uninitialised value(s)
==17533==    at 0x4F4362B: ??? (in /usr/lib64/atlas/libtatlas.so.3.10)
==17533==    by 0x4EB99E3: ATL_dgetf2 (in /usr/lib64/atlas/libtatlas.so.3.10)
==17533==    by 0x4EC42BF: ATL_dtgetrfC (in /usr/lib64/atlas/libtatlas.so.3.10)
==17533==    by 0x4EC42BF: ATL_dtgetrfC (in /usr/lib64/atlas/libtatlas.so.3.10)
==17533==    by 0x4EC42BF: ATL_dtgetrfC (in /usr/lib64/atlas/libtatlas.so.3.10)
==17533==    by 0x4EC42BF: ATL_dtgetrfC (in /usr/lib64/atlas/libtatlas.so.3.10)
==17533==    by 0x4F06538: atl_f77wrap_dgetrf_ (in /usr/lib64/atlas/libtatlas.so.3.10)
==17533==    by 0x4F07416: dgetrf_ (in /usr/lib64/atlas/libtatlas.so.3.10)
==17533==    by 0x400A29: main (fermi.c:50)
==17533==  Uninitialised value was created by a heap allocation
==17533==    at 0x4C2DB9D: malloc (vg_replace_malloc.c:299)
==17533==    by 0x40080B: main (fermi.c:22)


所以未初始化值的来源是这行代码:

temp = malloc(dim*dim*sizeof(double));


然后将m1其用于初始化传递到dgetrf_()第50行.

我不熟悉ATLAS库,但我想你应该以某种方式初始化temp变量.例如零初始化temp并calloc解决所有这些valgrind错误:

temp = calloc(dim*dim,sizeof(double));

        
@Emilie,使用未初始化的局部变量是c语言中的UB,请参阅http://stackoverflow.com/q/1597405/72178.我认为它仍然是UB,即使它乘以零`beta`.所以任何事情都可能发生,如果没有多线程版本的atlas,你可能无法在相同的代码上获得Valgrind错误.