linux-kernel - [PATCH] efi: Fix reference count leak in efivar_create_sysfs

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Date:   Thu, 28 May 2020 13:59:19 -0500
From:   wu000273@....edu
To:     kjlu@....edu
Cc:     wu000273@....edu, Ard Biesheuvel <ardb@...nel.org>,
        linux-efi@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH] efi: Fix reference count leak in efivar_create_sysfs_entry.

From: Qiushi Wu <wu000273@....edu>

kobject_init_and_add() should be handled when it return an error,
because 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. Previous
commit "b8eb718348b8" fixed a similar problem.

Signed-off-by: Qiushi Wu <wu000273@....edu>
---
 drivers/firmware/efi/efivars.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/firmware/efi/efivars.c b/drivers/firmware/efi/efivars.c
index 78ad1ba8c987..26528a46d99e 100644
--- a/drivers/firmware/efi/efivars.c
+++ b/drivers/firmware/efi/efivars.c
@@ -522,8 +522,10 @@ efivar_create_sysfs_entry(struct efivar_entry *new_var)
 	ret = kobject_init_and_add(&new_var->kobj, &efivar_ktype,
 				   NULL, "%s", short_name);
 	kfree(short_name);
-	if (ret)
+	if (ret) {
+		kobject_put(&new_var->kobj);
 		return ret;
+	}
 
 	kobject_uevent(&new_var->kobj, KOBJ_ADD);
 	if (efivar_entry_add(new_var, &efivar_sysfs_list)) {
-- 
2.17.1