[PATCH 3.4 16/19] lib/btree.c: fix leak of whole btree nodes

Greg Kroah-Hartman
2014-08-05T18:33:48Z

From: Minfei Huang <huangminfei@ucloud.cn>

commit c75b53af2f0043aff500af0a6f878497bef41bca upstream.

I use btree from 3.14-rc2 in my own module. When the btree module is
removed, a warning arises:

kmem_cache_destroy btree_node: Slab cache still has objects
CPU: 13 PID: 9150 Comm: rmmod Tainted: GF O 3.14.0-rc2 #1
Hardware name: Inspur NF5270M3/NF5270M3, BIOS CHEETAH_2.1.3 09/10/2013
Call Trace:
dump_stack+0x49/0x5d
kmem_cache_destroy+0xcf/0xe0
btree_module_exit+0x10/0x12 [btree]
SyS_delete_module+0x198/0x1f0
system_call_fastpath+0x16/0x1b

The cause is that it doesn't release the last btree node, when height = 1
and fill = 1.

[akpm@linux-foundation.org: remove unneeded test of NULL]
Signed-off-by: Minfei Huang <huangminfei@ucloud.cn>
Cc: Joern Engel <joern@logfs.org>
Cc: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
lib/btree.c | 1 +
1 file changed, 1 insertion(+)

--- a/lib/btree.c
+++ b/lib/btree.c
@@ -198,6 +198,7 @@ EXPORT_SYMBOL_GPL(btree_init);

void btree_destroy(struct btree_head *head)
{
+ mempool_free(head->node, head->mempool);
mempool_destroy(head->mempool);
head->mempool = NULL;
}