+ lib-btreec-fix-leak-of-whole-btree-nodes.patch added to -mm tree

+ lib-btreec-fix-leak-of-whole-btree-nodes.patch added to -mm tree

[akpm]

Subject: + lib-btreec-fix-leak-of-whole-btree-nodes.patch added to -mm tree
To: huangminfei@ucloud.cn,joern@logfs.org,johannes@sipsolutions.net
From: akpm@linux-foundation.org
Date: Thu, 08 May 2014 15:45:05 -0700


The patch titled
     Subject: lib/btree.c: fix leak of whole btree nodes
has been added to the -mm tree.  Its filename is
     lib-btreec-fix-leak-of-whole-btree-nodes.patch

This patch should soon appear at
    http://ozlabs.org/~akpm/mmots/broken-out/lib-btreec-fix-leak-of-whole-btree-nodes.patch
and later at
    http://ozlabs.org/~akpm/mmotm/broken-out/lib-btreec-fix-leak-of-whole-btree-nodes.patch

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------------------------------------------------------
From: Minfei Huang <huangminfei@ucloud.cn>
Subject: lib/btree.c: fix leak of whole btree nodes

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
ffff881ff8643b18 ffff881ffdc23ea8 ffffffff815a4ecc 0000000000000000
ffff881ff8643ac0 ffff881ffdc23ec8 ffffffff811610df 0000000000000880
ffffffffa057da60 ffff881ffdc23ed8 ffffffffa057d57c ffff881ffdc23f78
Call Trace:
[<ffffffff815a4ecc>] dump_stack+0x49/0x5d
[<ffffffff811610df>] kmem_cache_destroy+0xcf/0xe0
[<ffffffffa057d57c>] btree_module_exit+0x10/0x12 [btree]
[<ffffffff810d7948>] SyS_delete_module+0x198/0x1f0
[<ffffffff815aac89>] ? retint_swapgs+0xe/0x13
[<ffffffff810a561d>] ? trace_hardirqs_on_caller+0xfd/0x1c0
[<ffffffff812addde>] ? trace_hardirqs_on_thunk+0x3a/0x3f
[<ffffffff815b3652>] system_call_fastpath+0x16/0x1b

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

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>
---

 lib/btree.c |    2 ++
 1 file changed, 2 insertions(+)

diff -puN lib/btree.c~lib-btreec-fix-leak-of-whole-btree-nodes lib/btree.c
--- a/lib/btree.c~lib-btreec-fix-leak-of-whole-btree-nodes
+++ a/lib/btree.c
@@ -198,6 +198,8 @@ EXPORT_SYMBOL_GPL(btree_init);
 
 void btree_destroy(struct btree_head *head)
 {
+	if (head->node)
+		mempool_free(head->node, head->mempool);
 	mempool_destroy(head->mempool);
 	head->mempool = NULL;
 }
_

Patches currently in -mm which might be from huangminfei@ucloud.cn are

lib-btreec-fix-leak-of-whole-btree-nodes.patch
lib-btreec-fix-leak-of-whole-btree-nodes-fix.patch