[PATCH 4/6] mempolicy: fix refcount leak in mpol_set_shared_policy()
From: <hidden>
Date: 2012-05-30 09:03:26
Also in:
linux-mm, lkml
Subsystem:
memory management, memory management - memory policy and migration, the rest · Maintainers:
Andrew Morton, David Hildenbrand, Linus Torvalds
From: KOSAKI Motohiro <redacted> When shared_policy_replace() failure, new->policy is not freed correctly. The real problem is, shared mempolicy codes directly call kmem_cache_free() in multiple place. It can be easily mistake. This patch creates proper wrapper function and uses it. The bug was introduced pre-git age (IOW, before 2.6.12-rc2). Cc: Dave Jones <redacted>, Cc: Mel Gorman <mgorman@suse.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Christoph Lameter <redacted>, Cc: Andrew Morton <akpm@linux-foundation.org> Cc: <redacted> Signed-off-by: KOSAKI Motohiro <redacted> --- mm/mempolicy.c | 15 +++++++++------ 1 files changed, 9 insertions(+), 6 deletions(-)
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index d97d2db..7fb7d51 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c@@ -2150,12 +2150,17 @@ mpol_shared_policy_lookup(struct shared_policy *sp, unsigned long idx) return pol; } +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 void sp_node_init(struct sp_node *node, unsigned long start,
@@ -2320,7 +2325,7 @@ 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; }
@@ -2337,9 +2342,7 @@ 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); } spin_unlock(&p->lock); }
--
1.7.1