[PATCH 4.19 223/264] fs: dlm: fix configfs memory leak

Greg Kroah-Hartman
2020-10-27T14:26:59Z

From: Alexander Aring <aahringo@redhat.com>

[ Upstream commit 3d2825c8c6105b0f36f3ff72760799fa2e71420e ]

This patch fixes the following memory detected by kmemleak and umount
gfs2 filesystem which removed the last lockspace:

unreferenced object 0xffff9264f482f600 (size 192):
comm "dlm_controld", pid 325, jiffies 4294690276 (age 48.136s)
hex dump (first 32 bytes):
00 00 00 00 00 00 00 00 6e 6f 64 65 73 00 00 00 ........nodes...
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
backtrace:
[<00000000060481d7>] make_space+0x41/0x130
[<000000008d905d46>] configfs_mkdir+0x1a2/0x5f0
[<00000000729502cf>] vfs_mkdir+0x155/0x210
[<000000000369bcf1>] do_mkdirat+0x6d/0x110
[<00000000cc478a33>] do_syscall_64+0x33/0x40
[<00000000ce9ccf01>] entry_SYSCALL_64_after_hwframe+0x44/0xa9

The patch just remembers the "nodes" entry pointer in space as I think
it's created as subdirectory when parent "spaces" is created. In
function drop_space() we will lost the pointer reference to nds because
configfs_remove_default_groups(). However as this subdirectory is always
available when "spaces" exists it will just be freed when "spaces" will be
freed.

Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/dlm/config.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/fs/dlm/config.c b/fs/dlm/config.c
index 1270551d24e38..f13d865244501 100644
--- a/fs/dlm/config.c
+++ b/fs/dlm/config.c
@@ -218,6 +218,7 @@ struct dlm_space {
struct list_head members;
struct mutex members_lock;
int members_count;
+ struct dlm_nodes *nds;
};

struct dlm_comms {
@@ -426,6 +427,7 @@ static struct config_group *make_space(struct config_group *g, const char *name)
INIT_LIST_HEAD(&sp->members);
mutex_init(&sp->members_lock);
sp->members_count = 0;
+ sp->nds = nds;
return &sp->group;

fail:
@@ -447,6 +449,7 @@ static void drop_space(struct config_group *g, struct config_item *i)
static void release_space(struct config_item *i)
{
struct dlm_space *sp = config_item_to_space(i);
+ kfree(sp->nds);
kfree(sp);
}

--
2.25.1