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

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Date:   Mon,  7 Mar 2022 10:18:43 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Qiushi Wu <wu000273@....edu>,
        "Michael S. Tsirkin" <mst@...hat.com>,
        Sudip Mukherjee <sudipm.mukherjee@...il.com>
Subject: [PATCH 4.9 17/32] firmware: Fix a reference count leak.

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