It appears there is a nodemask miscalculation in the get_nodes() function in mm/mempolicy.c. This bug has two effects:
1. It is impossible to specify a length 1 nodemask. 2. It is impossible to specify a nodemask containing the last node. Brent have submmit a patch before v2.6.12, however, Andi revert his changed for ABI problem. I just resent this patch as RFC, for do not clear about what's the problem Andi have met. As manpage of set_mempolicy, If the value of maxnode is zero, the nodemask argument is ignored. but we should not ignore the nodemask when maxnode is 1. Signed-off-by: Yisheng Xie <[email protected]> --- mm/mempolicy.c | 1 - 1 file changed, 1 deletion(-) diff --git a/mm/mempolicy.c b/mm/mempolicy.c index a2af6d5..613e9d0 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -1265,7 +1265,6 @@ static int get_nodes(nodemask_t *nodes, const unsigned long __user *nmask, unsigned long nlongs; unsigned long endmask; - --maxnode; nodes_clear(*nodes); if (maxnode == 0 || !nmask) return 0; -- 1.7.12.4
