Description of problem:
When trying to add NUMA tuning in libvirt layer, found there is no error throwed
when setting with NUMA memory policy with obvious incorrect nodemask. Originally thought it was libnuma's problem, but tried with syscall directly then, still no error. This is high request to fix, as NUMA tuning is a feature request of libvirt for RHEL6.2.

=== System NUMA info ===

$ numactl --show
policy: default
preferred node: current
physcpubind: 0 1 
cpubind: 0 
nodebind: 0 
membind: 0 

=== Testing program to reproduce the problem ===

#include <stdio.h>
#include <stdlib.h>
#include <numa.h>
#include <errno.h>

#define _GNU_SOURCE        /* or _BSD_SOURCE or _SVID_SOURCE */
#include <unistd.h>
#include <sys/syscall.h>   /* For SYS_xxx definitions */

#define NUMA_NODES 10

int
main (int argc, char **argv) {
	if (numa_available() < 0) {
		fprintf(stderr, "NUMA is unavailable on your host\n");
		exit(EXIT_FAILURE);
	}

	numa_exit_on_error = 1;
	numa_exit_on_warn = 1;

	struct bitmask *mask = NULL;
	int i = 0;
	int mode = 2;
	int ret = -1;

	mask = numa_bitmask_alloc(NUMA_NODES);

	for (i = 0; i < NUMA_NODES; i++) {
		if (i % 2 == 0) {
			numa_bitmask_setbit(mask, i);
		}
	}

	errno = 0;

#if 0
	numa_set_bind_policy(1);
	numa_set_membind(mask);
#endif
	ret = syscall(__NR_set_mempolicy, 2, mask->maskp, NUMA_NODES);
	numa_set_bind_policy(0);

	if (errno) {
		fprintf(stderr, "Failed to set NUMA memory policy: %s\n",
                        strerror(errno));
		exit(EXIT_FAILURE);
	}

	printf("No error throwed when setting NUMA memory policy. ret = %d\n", ret);

	exit(EXIT_SUCCESS);
}

Version-Release number of selected component (if applicable):
kernel-2.6.32-122.el6.x86_64

How reproducible:
always

Steps to Reproduce:
1.
2.
3.
  
Actual results:


Expected results:


Additional info: