From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: Jianglei Nie <niejianglei2021@163.com>
Cc: ojeda@kernel.org, geert+renesas@glider.be,
linux-kernel@vger.kernel.org, kernel test robot <lkp@intel.com>
Subject: Re: [PATCH v2] auxdisplay: hd44780: Fix potential memory leak in hd44780_remove()
Date: Mon, 28 Nov 2022 12:45:39 +0200 [thread overview]
Message-ID: <Y4SRUwKFGJfwNZ2U@smile.fi.intel.com> (raw)
In-Reply-To: <20221128084421.8626-1-niejianglei2021@163.com>
On Mon, Nov 28, 2022 at 04:44:21PM +0800, Jianglei Nie wrote:
> hd44780_probe() allocates a memory chunk for hd with kzalloc() and
> makes "lcd->drvdata->hd44780" point to it. When we call hd44780_remove(),
> we should release all relevant memory and resource. But "lcd->drvdata
> ->hd44780" is not released, which will lead to a memory leak.
>
> We should release the "lcd->drvdata->hd44780" in hd44780_remove() to fix
> the memory leak bug.
Better now! See my comments below. After addressing them,
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> Fixes: 41c8d0adf3c4 ("auxdisplay: hd44780: Fix memory leak on ->remove()")
Fixes: 718e05ed92ec ("auxdisplay: Introduce hd44780_common.[ch]")
What you found has nothing to do with the issue. Issue has been introduced
later on.
> Reported-by: kernel test robot <lkp@intel.com>
> Signed-off-by: Jianglei Nie <niejianglei2021@163.com>
> ---
> drivers/auxdisplay/hd44780.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/drivers/auxdisplay/hd44780.c b/drivers/auxdisplay/hd44780.c
> index 8b2a0eb3f32a..f4800a946bd8 100644
> --- a/drivers/auxdisplay/hd44780.c
> +++ b/drivers/auxdisplay/hd44780.c
> @@ -322,8 +322,10 @@ static int hd44780_probe(struct platform_device *pdev)
> static int hd44780_remove(struct platform_device *pdev)
> {
> struct charlcd *lcd = platform_get_drvdata(pdev);
> + struct hd44780_common *hdc = (struct hd44780_common *)lcd->drvdata;
drvdata member is type of void *, no need to do an explicit casting as
per C standard.
> charlcd_unregister(lcd);
> + kfree(hdc->hd44780);
> kfree(lcd->drvdata);
>
> kfree(lcd);
> --
> 2.25.1
>
--
With Best Regards,
Andy Shevchenko
next prev parent reply other threads:[~2022-11-28 10:45 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-28 8:44 [PATCH v2] auxdisplay: hd44780: Fix potential memory leak in hd44780_remove() Jianglei Nie
2022-11-28 10:45 ` Andy Shevchenko [this message]
2022-11-28 10:59 ` Andy Shevchenko
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