selinux: use GFP_NOWAIT in the AVC kmem_caches

There is a strange __GFP_NOMEMALLOC usage pattern in SELinux, specifically GFP_ATOMIC | __GFP_NOMEMALLOC which doesn't make much sense. GFP_ATOMIC on its own allows to access memory reserves while __GFP_NOMEMALLOC dictates we cannot use memory reserves. Replace this with the much more sane GFP_NOWAIT in the AVC code as we can tolerate memory allocation failures in that code. Signed-off-by: Michal Hocko <[email protected]> Acked-by: Mel Gorman <[email protected]> Signed-off-by: Paul Moore <[email protected]>
gibsson · Aug 8, 2017 · 476accb · 476accb
1 parent af63f41
commit 476accb
Showing 1 changed file with 6 additions and 8 deletions.
diff --git a/security/selinux/avc.c b/security/selinux/avc.c
@@ -348,27 +348,26 @@ static struct avc_xperms_decision_node
 	struct avc_xperms_decision_node *xpd_node;
 	struct extended_perms_decision *xpd;
 
-	xpd_node = kmem_cache_zalloc(avc_xperms_decision_cachep,
-				GFP_ATOMIC | __GFP_NOMEMALLOC);
+	xpd_node = kmem_cache_zalloc(avc_xperms_decision_cachep, GFP_NOWAIT);
 	if (!xpd_node)
 		return NULL;
 
 	xpd = &xpd_node->xpd;
 	if (which & XPERMS_ALLOWED) {
 		xpd->allowed = kmem_cache_zalloc(avc_xperms_data_cachep,
-						GFP_ATOMIC | __GFP_NOMEMALLOC);
+						GFP_NOWAIT);
 		if (!xpd->allowed)
 			goto error;
 	}
 	if (which & XPERMS_AUDITALLOW) {
 		xpd->auditallow = kmem_cache_zalloc(avc_xperms_data_cachep,
-						GFP_ATOMIC | __GFP_NOMEMALLOC);
+						GFP_NOWAIT);
 		if (!xpd->auditallow)
 			goto error;
 	}
 	if (which & XPERMS_DONTAUDIT) {
 		xpd->dontaudit = kmem_cache_zalloc(avc_xperms_data_cachep,
-						GFP_ATOMIC | __GFP_NOMEMALLOC);
+						GFP_NOWAIT);
 		if (!xpd->dontaudit)
 			goto error;
 	}
@@ -396,8 +395,7 @@ static struct avc_xperms_node *avc_xperms_alloc(void)
 {
 	struct avc_xperms_node *xp_node;
 
-	xp_node = kmem_cache_zalloc(avc_xperms_cachep,
-				GFP_ATOMIC|__GFP_NOMEMALLOC);
+	xp_node = kmem_cache_zalloc(avc_xperms_cachep, GFP_NOWAIT);
 	if (!xp_node)
 		return xp_node;
 	INIT_LIST_HEAD(&xp_node->xpd_head);
@@ -550,7 +548,7 @@ static struct avc_node *avc_alloc_node(void)
 {
 	struct avc_node *node;
 
-	node = kmem_cache_zalloc(avc_node_cachep, GFP_ATOMIC|__GFP_NOMEMALLOC);
+	node = kmem_cache_zalloc(avc_node_cachep, GFP_NOWAIT);
 	if (!node)
 		goto out;