firmware: Fix a reference count leak.

commit fe3c60684377d5ad9b0569b87ed3e26e12c8173b upstream.

kobject_init_and_add() takes reference even when it fails.
If this function returns an error, kobject_put() must be called to
properly clean up the memory associated with the object.
Callback function fw_cfg_sysfs_release_entry() in kobject_put()
can handle the pointer "entry" properly.

Signed-off-by: Qiushi Wu <wu000273@umn.edu>
Link: https://lore.kernel.org/r/20200613190533.15712-1-wu000273@umn.edu
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
[sudip: adjust context]
Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/firmware/qemu_fw_cfg.c b/drivers/firmware/qemu_fw_cfg.c
index 595bf12e765382bdd8c3a2e146594c76a735a730..595cdb9fc97bc683a08e26cc3f92959e532f4db3 100644 (file)
--- a/drivers/firmware/qemu_fw_cfg.c
+++ b/drivers/firmware/qemu_fw_cfg.c
@@ -461,8 +461,10 @@ static int fw_cfg_register_file(const struct fw_cfg_file *f)
        /* register entry under "/sys/firmware/qemu_fw_cfg/by_key/" */
        err = kobject_init_and_add(&entry->kobj, &fw_cfg_sysfs_entry_ktype,
                                   fw_cfg_sel_ko, "%d", entry->f.select);
-       if (err)
-               goto err_register;
+       if (err) {
+               kobject_put(&entry->kobj);
+               return err;
+       }
 
        /* add raw binary content access */
        err = sysfs_create_bin_file(&entry->kobj, &fw_cfg_sysfs_attr_raw);
@@ -478,7 +480,6 @@ static int fw_cfg_register_file(const struct fw_cfg_file *f)
 
 err_add_raw:
        kobject_del(&entry->kobj);
-err_register:
        kfree(entry);
        return err;
 }