sysfs: kill an extra put in sysfs_create_link() failure path

There is a subtle bug in sysfs_create_link() failure path.  When
symlink creation fails because there's already a node with the same
name, the target sysfs_dirent is put twice - once by failure path of
sysfs_create_link() and once more when the symlink is released.

Fix it by making only the symlink node responsible for putting
target_sd.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Cc: Gabriel C <nix.or.die@googlemail.com>
Cc: Miles Lane <miles.lane@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 2 insertions, 0 deletions

diff --git a/fs/sysfs/symlink.c b/fs/sysfs/symlink.c
index 2f86e0422290..d056e9695cd6 100644
--- a/fs/sysfs/symlink.c
+++ b/fs/sysfs/symlink.c
@@ -86,7 +86,9 @@ int sysfs_create_link(struct kobject * kobj, struct kobject * target, const char
         sd = sysfs_new_dirent(name, S_IFLNK|S_IRWXUGO, SYSFS_KOBJ_LINK);
         if (!sd)
                 goto out_put;
+
         sd->s_elem.symlink.target_sd = target_sd;
+        target_sd = NULL;       /* reference is now owned by the symlink */
 
         sysfs_addrm_start(&acxt, parent_sd);