cgroup: fix possible memory leak

There's a leak if copy_from_user() returns failure.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Paul Menage <menage@google.com>
Cc: Cedric Le Goater <clg@fr.ibm.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 5 insertions, 2 deletions

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 657f8f8d93a5..28debe4e1488 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -1424,14 +1424,17 @@ static ssize_t cgroup_write_string(struct cgroup *cgrp, struct cftype *cft,
                 if (buffer == NULL)
                         return -ENOMEM;
         }
-        if (nbytes && copy_from_user(buffer, userbuf, nbytes))
-                return -EFAULT;
+        if (nbytes && copy_from_user(buffer, userbuf, nbytes)) {
+                retval = -EFAULT;
+                goto out;
+        }
 
         buffer[nbytes] = 0;     /* nul-terminate */
         strstrip(buffer);
         retval = cft->write_string(cgrp, cft, buffer);
         if (!retval)
                 retval = nbytes;
+out:
         if (buffer != local_buffer)
                 kfree(buffer);
         return retval;