* [PATCH 0/6] treewide: test clock rate to avoid division by 0
@ 2016-03-02 22:33 Wolfram Sang
2016-03-02 22:33 ` [PATCH 3/6] pwm: pwm-img: " Wolfram Sang
2016-03-02 22:33 ` [PATCH 4/6] pwm: pwm-lpc18xx-sct: " Wolfram Sang
0 siblings, 2 replies; 6+ messages in thread
From: Wolfram Sang @ 2016-03-02 22:33 UTC (permalink / raw)
To: linux-kernel
Cc: linux-renesas-soc, linux-arm-kernel, linux-ide, linux-pwm,
linux-watchdog, netdev
Here is the outcome of researching if the result of clk_get_rate() was directly
used as a divisor without checking if it is 0. Inspired by a Coverity report.
Wolfram Sang (6):
ide: palm_bk3710: test clock rate to avoid division by 0
net: ethernet: renesas: ravb_main: test clock rate to avoid division
by 0
pwm: pwm-img: test clock rate to avoid division by 0
pwm: pwm-lpc18xx-sct: test clock rate to avoid division by 0
watchdog: atlas7_wdt: test clock rate to avoid division by 0
watchdog: tangox_wdt: test clock rate to avoid division by 0
drivers/ide/palm_bk3710.c | 2 ++
drivers/net/ethernet/renesas/ravb_main.c | 3 +++
drivers/pwm/pwm-img.c | 5 +++++
drivers/pwm/pwm-lpc18xx-sct.c | 2 ++
drivers/watchdog/atlas7_wdt.c | 5 +++++
drivers/watchdog/tangox_wdt.c | 2 ++
6 files changed, 19 insertions(+)
--
2.7.0
^ permalink raw reply [flat|nested] 6+ messages in thread* [PATCH 3/6] pwm: pwm-img: test clock rate to avoid division by 0
2016-03-02 22:33 [PATCH 0/6] treewide: test clock rate to avoid division by 0 Wolfram Sang
@ 2016-03-02 22:33 ` Wolfram Sang
2016-03-04 15:01 ` Thierry Reding
2016-03-02 22:33 ` [PATCH 4/6] pwm: pwm-lpc18xx-sct: " Wolfram Sang
1 sibling, 1 reply; 6+ messages in thread
From: Wolfram Sang @ 2016-03-02 22:33 UTC (permalink / raw)
To: linux-kernel; +Cc: linux-renesas-soc, Thierry Reding, linux-pwm
From: Wolfram Sang <wsa+renesas@sang-engineering.com>
The clk API may return 0 on clk_get_rate, so we should check the result before
using it as a divisor.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
---
Should go individually via subsystem tree.
drivers/pwm/pwm-img.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/drivers/pwm/pwm-img.c b/drivers/pwm/pwm-img.c
index 8a029f9bc18cb0..2fb30deee34570 100644
--- a/drivers/pwm/pwm-img.c
+++ b/drivers/pwm/pwm-img.c
@@ -237,6 +237,11 @@ static int img_pwm_probe(struct platform_device *pdev)
}
clk_rate = clk_get_rate(pwm->pwm_clk);
+ if (!clk_rate) {
+ dev_err(&pdev->dev, "pwm clock has no frequency\n");
+ ret = -EINVAL;
+ goto disable_pwmclk;
+ }
/* The maximum input clock divider is 512 */
val = (u64)NSEC_PER_SEC * 512 * pwm->data->max_timebase;
--
2.7.0
^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [PATCH 3/6] pwm: pwm-img: test clock rate to avoid division by 0
2016-03-02 22:33 ` [PATCH 3/6] pwm: pwm-img: " Wolfram Sang
@ 2016-03-04 15:01 ` Thierry Reding
0 siblings, 0 replies; 6+ messages in thread
From: Thierry Reding @ 2016-03-04 15:01 UTC (permalink / raw)
To: Wolfram Sang; +Cc: linux-kernel, linux-renesas-soc, linux-pwm
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On Wed, Mar 02, 2016 at 11:33:34PM +0100, Wolfram Sang wrote:
> From: Wolfram Sang <wsa+renesas@sang-engineering.com>
>
> The clk API may return 0 on clk_get_rate, so we should check the result before
> using it as a divisor.
>
> Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
> ---
>
> Should go individually via subsystem tree.
>
> drivers/pwm/pwm-img.c | 5 +++++
> 1 file changed, 5 insertions(+)
Applied, thanks.
Thierry
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^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH 4/6] pwm: pwm-lpc18xx-sct: test clock rate to avoid division by 0
2016-03-02 22:33 [PATCH 0/6] treewide: test clock rate to avoid division by 0 Wolfram Sang
2016-03-02 22:33 ` [PATCH 3/6] pwm: pwm-img: " Wolfram Sang
@ 2016-03-02 22:33 ` Wolfram Sang
2016-03-02 22:44 ` Joachim Eastwood
1 sibling, 1 reply; 6+ messages in thread
From: Wolfram Sang @ 2016-03-02 22:33 UTC (permalink / raw)
To: linux-kernel
Cc: linux-renesas-soc, linux-pwm, Joachim Eastwood, Thierry Reding,
linux-arm-kernel
From: Wolfram Sang <wsa+renesas@sang-engineering.com>
The clk API may return 0 on clk_get_rate, so we should check the result before
using it as a divisor.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
---
Should go individually via subsystem tree.
drivers/pwm/pwm-lpc18xx-sct.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/pwm/pwm-lpc18xx-sct.c b/drivers/pwm/pwm-lpc18xx-sct.c
index 9163085101bc94..6487962c355c03 100644
--- a/drivers/pwm/pwm-lpc18xx-sct.c
+++ b/drivers/pwm/pwm-lpc18xx-sct.c
@@ -360,6 +360,8 @@ static int lpc18xx_pwm_probe(struct platform_device *pdev)
}
lpc18xx_pwm->clk_rate = clk_get_rate(lpc18xx_pwm->pwm_clk);
+ if (!lpc18xx_pwm->clk_rate)
+ return -EINVAL;
mutex_init(&lpc18xx_pwm->res_lock);
mutex_init(&lpc18xx_pwm->period_lock);
--
2.7.0
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH 4/6] pwm: pwm-lpc18xx-sct: test clock rate to avoid division by 0
2016-03-02 22:33 ` [PATCH 4/6] pwm: pwm-lpc18xx-sct: " Wolfram Sang
@ 2016-03-02 22:44 ` Joachim Eastwood
2016-03-02 22:58 ` Wolfram Sang
0 siblings, 1 reply; 6+ messages in thread
From: Joachim Eastwood @ 2016-03-02 22:44 UTC (permalink / raw)
To: Wolfram Sang
Cc: linux-kernel@vger.kernel.org, linux-renesas-soc, Thierry Reding,
linux-pwm, linux-arm-kernel@lists.infradead.org,
Ariel D'Alessandro
Hi Wolfram,
On 2 March 2016 at 23:33, Wolfram Sang <wsa@the-dreams.de> wrote:
> From: Wolfram Sang <wsa+renesas@sang-engineering.com>
>
> The clk API may return 0 on clk_get_rate, so we should check the result before
> using it as a divisor.
>
> Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
> ---
>
> Should go individually via subsystem tree.
>
> drivers/pwm/pwm-lpc18xx-sct.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/drivers/pwm/pwm-lpc18xx-sct.c b/drivers/pwm/pwm-lpc18xx-sct.c
> index 9163085101bc94..6487962c355c03 100644
> --- a/drivers/pwm/pwm-lpc18xx-sct.c
> +++ b/drivers/pwm/pwm-lpc18xx-sct.c
> @@ -360,6 +360,8 @@ static int lpc18xx_pwm_probe(struct platform_device *pdev)
> }
>
> lpc18xx_pwm->clk_rate = clk_get_rate(lpc18xx_pwm->pwm_clk);
> + if (!lpc18xx_pwm->clk_rate)
> + return -EINVAL;
This needs to be:
if (!lpc18xx_pwm->clk_rate) {
ret = -EINVAL;
goto disable_pwmclk;
}
I would also prefer an explicit check against 0 here. ie.:
'lpc18xx_pwm->clk_rate == 0'
A dev_err() message would also be nice to have.
regards,
Joachim Eastwood
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH 4/6] pwm: pwm-lpc18xx-sct: test clock rate to avoid division by 0
2016-03-02 22:44 ` Joachim Eastwood
@ 2016-03-02 22:58 ` Wolfram Sang
0 siblings, 0 replies; 6+ messages in thread
From: Wolfram Sang @ 2016-03-02 22:58 UTC (permalink / raw)
To: Joachim Eastwood
Cc: linux-kernel@vger.kernel.org, linux-renesas-soc, Thierry Reding,
linux-pwm, linux-arm-kernel@lists.infradead.org,
Ariel D'Alessandro
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On Wed, Mar 02, 2016 at 11:44:02PM +0100, Joachim Eastwood wrote:
> Hi Wolfram,
>
> On 2 March 2016 at 23:33, Wolfram Sang <wsa@the-dreams.de> wrote:
> > From: Wolfram Sang <wsa+renesas@sang-engineering.com>
> >
> > The clk API may return 0 on clk_get_rate, so we should check the result before
> > using it as a divisor.
> >
> > Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
> > ---
> >
> > Should go individually via subsystem tree.
> >
> > drivers/pwm/pwm-lpc18xx-sct.c | 2 ++
> > 1 file changed, 2 insertions(+)
> >
> > diff --git a/drivers/pwm/pwm-lpc18xx-sct.c b/drivers/pwm/pwm-lpc18xx-sct.c
> > index 9163085101bc94..6487962c355c03 100644
> > --- a/drivers/pwm/pwm-lpc18xx-sct.c
> > +++ b/drivers/pwm/pwm-lpc18xx-sct.c
> > @@ -360,6 +360,8 @@ static int lpc18xx_pwm_probe(struct platform_device *pdev)
> > }
> >
> > lpc18xx_pwm->clk_rate = clk_get_rate(lpc18xx_pwm->pwm_clk);
> > + if (!lpc18xx_pwm->clk_rate)
> > + return -EINVAL;
>
> This needs to be:
> if (!lpc18xx_pwm->clk_rate) {
> ret = -EINVAL;
> goto disable_pwmclk;
> }
Yes, that slipped through. Thanks!
> I would also prefer an explicit check against 0 here. ie.:
Well, I like the reading "if not rate then error"
Will send V2 now...
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^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2016-03-04 15:01 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
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2016-03-02 22:33 [PATCH 0/6] treewide: test clock rate to avoid division by 0 Wolfram Sang
2016-03-02 22:33 ` [PATCH 3/6] pwm: pwm-img: " Wolfram Sang
2016-03-04 15:01 ` Thierry Reding
2016-03-02 22:33 ` [PATCH 4/6] pwm: pwm-lpc18xx-sct: " Wolfram Sang
2016-03-02 22:44 ` Joachim Eastwood
2016-03-02 22:58 ` Wolfram Sang
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