From: David Rientjes <rientjes@google.com>
Date: Fri, 4 Jul 2008 19:24:13 +0000 (-0700)
Subject: mempolicy: mask off internal flags for userspace API
X-Git-Tag: v2.6.26-rc9~8
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=d79df630f622806c4d0e116fbaf6ebf6baf53461;p=linux-2.6

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 a37a5034f6..c94e58b192 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -729,7 +729,11 @@ static long do_get_mempolicy(int *policy, nodemask_t *nmask,
 	} 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) {