mempolicy: mask off internal flags for userspace API
Flags considered internal to the mempolicy kernel code are stored as part
of the "flags" member of struct mempolicy.
Before exposing a policy type to userspace via get_mempolicy(), these
internal flags must be masked. Flags exposed to userspace, however,
should still be returned to the user.
Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index a37a503..c94e58b 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -729,7 +729,11 @@
} else {
*policy = pol == &default_policy ? MPOL_DEFAULT :
pol->mode;
- *policy |= pol->flags;
+ /*
+ * Internal mempolicy flags must be masked off before exposing
+ * the policy to userspace.
+ */
+ *policy |= (pol->flags & MPOL_MODE_FLAGS);
}
if (vma) {