linux-kernel - Re: [PATCH] fail_function: remove a redundant mutex unlock

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Date:   Wed, 11 Nov 2020 18:31:29 +0900
From:   Masami Hiramatsu <mhiramat@...nel.org>
To:     Luo Meng <luomeng12@...wei.com>
Cc:     <jbacik@...com>, <ast@...nel.org>, <linux-kernel@...r.kernel.org>,
        stable@...nel.vger.org
Subject: Re: [PATCH] fail_function: remove a redundant mutex unlock

Hi Luo,

On Tue, 10 Nov 2020 16:42:45 +0800
Luo Meng <luomeng12@...wei.com> wrote:

> Fix a mutex_unlock() issue where before copy_from_user() is
> not called mutex_locked.

Oops, thank you for the fix.

Acked-by: Masami Hiramatsu <mhiramat@...nel.org>

> 
> Fixes: 4b1a29a7f542 ("error-injection: Support fault injection framework")
> Reported-by: Hulk Robot <hulkci@...wei.com>
> Signed-off-by: Luo Meng <luomeng12@...wei.com>
> ---
>  kernel/fail_function.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/kernel/fail_function.c b/kernel/fail_function.c
> index 63b349168da7..b0b1ad93fa95 100644
> --- a/kernel/fail_function.c
> +++ b/kernel/fail_function.c
> @@ -253,7 +253,7 @@ static ssize_t fei_write(struct file *file, const char __user *buffer,
>  
>  	if (copy_from_user(buf, buffer, count)) {
>  		ret = -EFAULT;
> -		goto out;
> +		goto out_free;
>  	}
>  	buf[count] = '\0';
>  	sym = strstrip(buf);
> @@ -307,8 +307,9 @@ static ssize_t fei_write(struct file *file, const char __user *buffer,
>  		ret = count;
>  	}
>  out:
> -	kfree(buf);
>  	mutex_unlock(&fei_lock);
> +out_free:
> +	kfree(buf);
>  	return ret;
>  }
>  
> -- 
> 2.25.4
> 


-- 
Masami Hiramatsu <mhiramat@...nel.org>