From: Dan Carpenter <dan.carpenter@oracle.com>
To: "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>
Cc: Jacek Anaszewski <jacek.anaszewski@gmail.com>,
Pavel Machek <pavel@ucw.cz>, Dan Murphy <dmurphy@ti.com>,
linux-leds@vger.kernel.org, kernel-janitors@vger.kernel.org
Subject: Re: [PATCH] led: triggers: Fix NULL dereference in led_trigger_set() error handling
Date: Thu, 5 Sep 2019 16:04:06 +0300 [thread overview]
Message-ID: <20190905130406.GE3093@kadam> (raw)
In-Reply-To: <20190905120626.hyegecmy6hf5lvhj@pengutronix.de>
On Thu, Sep 05, 2019 at 02:06:26PM +0200, Uwe Kleine-König wrote:
> Hello,
>
> On Thu, Sep 05, 2019 at 12:57:28PM +0300, Dan Carpenter wrote:
> > The problem is we set "led_cdev->trigger = NULL;" and then dereference
> > it when we call write_lock_irqsave():
> >
> > write_lock_irqsave(&led_cdev->trigger->leddev_list_lock, flags);
> > ^^^^^^^^^^^^^^^^^
> >
> > Fixes: 2282e125a406 ("leds: triggers: let struct led_trigger::activate() return an error code")
> > Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
>
> Obviously right. Thanks for catching.
>
> Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
>
> Did you find this at runtime or by using some static checker?
Yes. It's a new one that I'm working on.
It's a tricky thing because it turns out Smatch thinks a whole lot of
pointers are definitely NULL when they aren't. For example, if the
struct is allocated with kzalloc() and Smatch doesn't see where the
pointer is assigned.
regards,
dan carpenter
prev parent reply other threads:[~2019-09-05 13:04 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-05 9:57 [PATCH] led: triggers: Fix NULL dereference in led_trigger_set() error handling Dan Carpenter
2019-09-05 11:22 ` Oleh Kravchenko
2019-09-05 12:06 ` Uwe Kleine-König
2019-09-05 12:23 ` Oleh Kravchenko
2019-09-05 12:46 ` Uwe Kleine-König
2019-09-05 20:41 ` Jacek Anaszewski
2019-09-05 13:32 ` Dan Carpenter
2019-09-08 9:46 ` Oleh Kravchenko
2019-09-05 12:39 ` Oleh Kravchenko
2019-09-05 13:04 ` Dan Carpenter [this message]
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