From: Yisheng Xie <xieyisheng1@huawei.com>
Date: Thu, 1 Feb 2018 00:16:15 +0000 (-0800)
Subject: mm/mempolicy: add nodes_empty check in SYSC_migrate_pages
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=305e56756da71e0ef7cc8d91b8e66fafbb6e5d5a;p=GitHub%2Fmoto-9609%2Fandroid_kernel_motorola_exynos9610.git

mm/mempolicy: add nodes_empty check in SYSC_migrate_pages


[ Upstream commit 0486a38bcc4749808edbc848f1bcf232042770fc ]

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>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 80b67805b51d..2d3077ce50cd 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -1440,10 +1440,14 @@ 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)