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mm/mempolicy: add nodes_empty check in SYSC_migrate_pages

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As in manpage of migrate_pages, the errno should be set to EINVAL when
none of the node IDs specified by new_nodes are on-line and allowed by
the process's current cpuset context, or none of the specified nodes
contain memory.  However, when test by following case:

	new_nodes = 0;
	old_nodes = 0xf;
	ret = migrate_pages(pid, old_nodes, new_nodes, MAX);

The ret will be 0 and no errno is set.  As the new_nodes is empty, we
should expect EINVAL as documented.

To fix the case like above, this patch check whether target nodes AND
current task_nodes is empty, and then check whether AND
node_states[N_MEMORY] is empty.

Link: http://lkml.kernel.org/r/1510882624-44342-4-git-send-email-xieyisheng1@huawei.com
Signed-off-by: Yisheng Xie <xieyisheng1@huawei.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Chris Salls <salls@cs.ucsb.edu>
Cc: Christopher Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Tan Xiaojun <tanxiaojun@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Yisheng Xie 2018-01-31 16:16:15 -08:00 committed by Linus Torvalds
parent 56521e7a02
commit 0486a38bcc
1 changed files with 7 additions and 3 deletions
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10
mm/mempolicy.c
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@ -1433,10 +1433,14 @@ SYSCALL_DEFINE4(migrate_pages, pid_t, pid, unsigned long, maxnode,
goto out_put;
}
if (!nodes_subset(*new, node_states[N_MEMORY])) {
err = -EINVAL;
task_nodes = cpuset_mems_allowed(current);
nodes_and(*new, *new, task_nodes);
if (nodes_empty(*new))
goto out_put;
nodes_and(*new, *new, node_states[N_MEMORY]);
if (nodes_empty(*new))
goto out_put;
}
err = security_task_movememory(task);
if (err)