无法确定valgrind错误的原因

Question

当我在代码的摘录上运行valgrind时，它告诉我我的错误在于这行代码，但我似乎无法弄明白（vector_size if int类型）：

float *rotations = (float *) calloc(vector_size*vector_size, sizeof(float));

这是valgrind的输出：

Invalid write of size 4
    ==5488==    at 0x109272: main (rotate_vector.c:20)
    ==5488==  Address 0x4a47164 is 0 bytes after a block of size 196 alloc'd
    ==5488==    at 0x4839775: calloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
    ==5488==    by 0x1091D5: main (rotate_vector.c:8)
    ==5488== 
    ==5488== 
    ==5488== Process terminating with default action of signal 11 (SIGSEGV)
    ==5488==  Access not within mapped region at address 0x4E47018
    ==5488==    at 0x109272: main (rotate_vector.c:20)
    ==5488==  If you believe this happened as a result of a stack
    ==5488==  overflow in your program's main thread (unlikely but
    ==5488==  possible), you can try to increase the size of the
    ==5488==  main thread stack using the --main-stacksize= flag.
    ==5488==  The main thread stack size used in this run was 8388608.

有关如何修复的任何建议？

Answer 1

当我忘记将1添加到您想要分配的大小时，我通常会遇到这些错误。

所以它可能来自你的calloc尺寸，尝试加1。

你基本上写的是你分配的内存。

编辑：Valgrind告诉你，你正试图在你分配的内存之外（和之后）写4个字节（浮点大小）。因此，您需要再分配4个字节来存储最后一个浮点值。