[PATCH] net: ipv4: current group_info should be put after using.

["Wang, Xiaoming" <xiaoming.wang@intel.com>]

There is a memory leak in ping. Current group_info had been got in 
ping_init_sock and group_info->usage increased. 
But the usage hasn't decreased anywhere in ping.
This will make this group_info never freed and cause memory leak.

unreferenced object 0xcd0e8840 (size 192):
  comm "dumpstate", pid 7583, jiffies 78360 (age 91.810s)
  hex dump (first 32 bytes):
    02 00 00 00 06 00 00 00 01 00 00 00 ef 03 00 00  ................
    f1 03 00 00 f7 03 00 00 04 04 00 00 bb 0b 00 00  ................
  backtrace:
    [<c1a6bbfc>] kmemleak_alloc+0x3c/0xa0
    [<c1320457>] __kmalloc+0xe7/0x1d0
    [<c1267c04>] groups_alloc+0x34/0xb0
    [<c1267e5c>] SyS_setgroups+0x3c/0xf0
    [<c1a864a8>] syscall_call+0x7/0xb
    [<ffffffff>] 0xffffffff

Signed-off-by: Chuansheng Liu <chuansheng.liu@intel.com>
Signed-off-by: Zhang Dongxing <dongxing.zhang@intel.com>
Signed-off-by: xiaoming wang <xiaoming.wang@intel.com>
---
 net/ipv4/ping.c |   11 ++++++++---
 1 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/net/ipv4/ping.c b/net/ipv4/ping.c
index f4b19e5..2af7b1f 100644
--- a/net/ipv4/ping.c
+++ b/net/ipv4/ping.c
@@ -255,23 +255,28 @@ int ping_init_sock(struct sock *sk)
 	struct group_info *group_info = get_current_groups();
 	int i, j, count = group_info->ngroups;
 	kgid_t low, high;
+	int ret = 0;
 
 	inet_get_ping_group_range_net(net, &low, &high);
 	if (gid_lte(low, group) && gid_lte(group, high))
-		return 0;
+		goto out_release_group;
 
 	for (i = 0; i < group_info->nblocks; i++) {
 		int cp_count = min_t(int, NGROUPS_PER_BLOCK, count);
 		for (j = 0; j < cp_count; j++) {
 			kgid_t gid = group_info->blocks[i][j];
 			if (gid_lte(low, gid) && gid_lte(gid, high))
-				return 0;
+				goto out_release_group;
 		}
 
 		count -= cp_count;
 	}
 
-	return -EACCES;
+	ret = -EACCES;
+
+out_release_group:
+	put_group_info(group_info);
+	return ret;
 }
 EXPORT_SYMBOL_GPL(ping_init_sock);
 
-- 
1.7.1