linux-kernel - Re: [PATCH 4.19 27/57] cxgb4: fix a memory leak bug

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Date:   Mon, 9 Sep 2019 15:06:43 +0200
From:   Pavel Machek <pavel@...x.de>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:     linux-kernel@...r.kernel.org, stable@...r.kernel.org,
        Wenwen Wang <wenwen@...uga.edu>,
        "David S. Miller" <davem@...emloft.net>,
        Sasha Levin <sashal@...nel.org>
Subject: Re: [PATCH 4.19 27/57] cxgb4: fix a memory leak bug

On Sun 2019-09-08 13:41:51, Greg Kroah-Hartman wrote:
> [ Upstream commit c554336efa9bbc28d6ec14efbee3c7d63c61a34f ]
> 
> In blocked_fl_write(), 't' is not deallocated if bitmap_parse_user() fails,
> leading to a memory leak bug. To fix this issue, free t before returning
> the error.

The code is quite strange ... it seems to use kvfree when free would
be enough. Is that worth fixing? blocked_fl_read() seems to have same
problem.

Best regards,

								Pavel

> Signed-off-by: Wenwen Wang <wenwen@...uga.edu>
> Signed-off-by: David S. Miller <davem@...emloft.net>
> Signed-off-by: Sasha Levin <sashal@...nel.org>
> ---
>  drivers/net/ethernet/chelsio/cxgb4/cxgb4_debugfs.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/net/ethernet/chelsio/cxgb4/cxgb4_debugfs.c b/drivers/net/ethernet/chelsio/cxgb4/cxgb4_debugfs.c
> index 0f72f9c4ec74c..b429b726b987b 100644
> --- a/drivers/net/ethernet/chelsio/cxgb4/cxgb4_debugfs.c
> +++ b/drivers/net/ethernet/chelsio/cxgb4/cxgb4_debugfs.c
> @@ -3276,8 +3276,10 @@ static ssize_t blocked_fl_write(struct file *filp, const char __user *ubuf,
>  		return -ENOMEM;
>  
>  	err = bitmap_parse_user(ubuf, count, t, adap->sge.egr_sz);
> -	if (err)
> +	if (err) {
> +		kvfree(t);
>  		return err;
> +	}
>  
>  	bitmap_copy(adap->sge.blocked_fl, t, adap->sge.egr_sz);
>  	kvfree(t);

-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

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