From 239024453a2834a2307ef0ed9488346049f7acc1 Mon Sep 17 00:00:00 2001 From: KOSAKI Motohiro Date: Fri, 28 Sep 2012 10:19:11 +1000 Subject: [PATCH] mempolicy: fix refcount leak in mpol_set_shared_policy() When shared_policy_replace() fails to allocate new->policy is not freed correctly by mpol_set_shared_policy(). The problem is that shared mempolicy code directly call kmem_cache_free() in multiple places where it is easy to make a mistake. This patch creates an sp_free wrapper function and uses it. The bug was introduced pre-git age (IOW, before 2.6.12-rc2). [mgorman@suse.de: Editted changelog] Signed-off-by: KOSAKI Motohiro Signed-off-by: Mel Gorman Reviewed-by: Christoph Lameter Cc: Josh Boyer Signed-off-by: Andrew Morton --- mm/mempolicy.c | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-) diff --git a/mm/mempolicy.c b/mm/mempolicy.c index bc23aa2d301b..6e2cd87e0313 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -2300,12 +2300,17 @@ out: return ret; } +static void sp_free(struct sp_node *n) +{ + mpol_put(n->policy); + kmem_cache_free(sn_cache, n); +} + static void sp_delete(struct shared_policy *sp, struct sp_node *n) { pr_debug("deleting %lx-l%lx\n", n->start, n->end); rb_erase(&n->nd, &sp->root); - mpol_put(n->policy); - kmem_cache_free(sn_cache, n); + sp_free(n); } static struct sp_node *sp_alloc(unsigned long start, unsigned long end, @@ -2444,7 +2449,7 @@ int mpol_set_shared_policy(struct shared_policy *info, } err = shared_policy_replace(info, vma->vm_pgoff, vma->vm_pgoff+sz, new); if (err && new) - kmem_cache_free(sn_cache, new); + sp_free(new); return err; } @@ -2461,9 +2466,7 @@ void mpol_free_shared_policy(struct shared_policy *p) while (next) { n = rb_entry(next, struct sp_node, nd); next = rb_next(&n->nd); - rb_erase(&n->nd, &p->root); - mpol_put(n->policy); - kmem_cache_free(sn_cache, n); + sp_delete(p, n); } mutex_unlock(&p->mutex); } -- 2.39.5