As Xiaojun reported the ltp of migrate_pages01 will failed on ARCH arm64
system whoes has 4 nodes[0...3], all have memory and CONFIG_NODES_SHIFT=2:
migrate_pages01 0 TINFO : test_invalid_nodes
migrate_pages01 14 TFAIL : migrate_pages_common.c:45: unexpected failure - returned value = 0, expected: -1
migrate_pages01 15 TFAIL : migrate_pages_common.c:55: call succeeded unexpectedly
In this case the test_invalid_nodes of migrate_pages01 will call:
SYSC_migrate_pages as:
migrate_pages(0, , {0x0000000000000001}, 64, , {0x0000000000000010}, 64) = 0
For MAX_NUMNODES is 4, so 0x10 nodemask will tread as empty set which makes
nodes_subset(*new, node_states[N_MEMORY])
return true, as empty set is subset of any set.
So this is a common issue which also can happens in X86_64 system eg. 8 nodes[0..7],
all with memory and CONFIG_NODES_SHIFT=3. Fix it by adding node_empty check in
SYSC_migrate_pages.
Reported-by: Tan Xiaojun <tanxiaojun@xxxxxxxxxx>
Signed-off-by: Yisheng Xie <xieyisheng1@xxxxxxxxxx>
---
mm/mempolicy.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index a2af6d5..1dfd3cc 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -1388,6 +1388,11 @@ static int copy_nodes_to_user(unsigned long __user *mask, unsigned long maxnode,
if (err)
goto out;
+ if (nodes_empty(*new)) {
+ err = -EINVAL;
+ goto out;
+ }
+
/* Find the mm_struct */
rcu_read_lock();
task = pid ? find_task_by_vpid(pid) : current;
--
1.7.12.4
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