[PATCH 4.9 17/32] firmware: Fix a reference count leak.

Greg Kroah-Hartman
2022-03-07T09:20:01Z

From: Qiushi Wu <wu000273@umn.edu>

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>
---
drivers/firmware/qemu_fw_cfg.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)

--- 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 st
/* 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 st

err_add_raw:
kobject_del(&entry->kobj);
-err_register:
kfree(entry);
return err;
}