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

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Date:   Fri, 29 May 2020 18:58:42 +0200
From:   Ard Biesheuvel <ardb@...nel.org>
To:     wu000273@....edu
Cc:     kjlu@....edu, linux-efi <linux-efi@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] efi: Fix reference count leak in efivar_create_sysfs_entry.

On Thu, 28 May 2020 at 20:59, <wu000273@....edu> wrote:
>
> 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>

This one is already fixed in linux-next

> ---
>  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
>