In evm_led_setup(), the allocation result of platform_device_alloc() and
platform_device_add_data() should be checked.
Signed-off-by: Gen Zhang <[email protected]>
---
diff --git a/arch/arm/mach-davinci/board-dm644x-evm.c b/arch/arm/mach-davinci/board-dm644x-evm.c
index 9d87d4e..9cd2785 100644
--- a/arch/arm/mach-davinci/board-dm644x-evm.c
+++ b/arch/arm/mach-davinci/board-dm644x-evm.c
@@ -352,15 +352,20 @@ evm_led_setup(struct i2c_client *client, int gpio, unsigned ngpio, void *c)
* device unregistration ...
*/
evm_led_dev = platform_device_alloc("leds-gpio", 0);
- platform_device_add_data(evm_led_dev,
+ if (!evm_led_dev)
+ return -ENOMEM;
+ status = platform_device_add_data(evm_led_dev,
&evm_led_data, sizeof evm_led_data);
+ if (status)
+ goto err;
evm_led_dev->dev.parent = &client->dev;
status = platform_device_add(evm_led_dev);
- if (status < 0) {
- platform_device_put(evm_led_dev);
- evm_led_dev = NULL;
- }
+ if (status)
+ goto err;
+err:
+ platform_device_put(evm_led_dev);
+ evm_led_dev = NULL;
return status;
}
On Fri, Dec 27, 2019 at 10:39:21AM +0800, Gen Zhang wrote:
> In evm_led_setup(), the allocation result of platform_device_alloc() and
> platform_device_add_data() should be checked.
>
> Signed-off-by: Gen Zhang <[email protected]>
> ---
> diff --git a/arch/arm/mach-davinci/board-dm644x-evm.c b/arch/arm/mach-davinci/board-dm644x-evm.c
> index 9d87d4e..9cd2785 100644
> --- a/arch/arm/mach-davinci/board-dm644x-evm.c
> +++ b/arch/arm/mach-davinci/board-dm644x-evm.c
> @@ -352,15 +352,20 @@ evm_led_setup(struct i2c_client *client, int gpio, unsigned ngpio, void *c)
> * device unregistration ...
> */
> evm_led_dev = platform_device_alloc("leds-gpio", 0);
> - platform_device_add_data(evm_led_dev,
> + if (!evm_led_dev)
> + return -ENOMEM;
> + status = platform_device_add_data(evm_led_dev,
> &evm_led_data, sizeof evm_led_data);
> + if (status)
> + goto err;
>
> evm_led_dev->dev.parent = &client->dev;
> status = platform_device_add(evm_led_dev);
> - if (status < 0) {
> - platform_device_put(evm_led_dev);
> - evm_led_dev = NULL;
> - }
> + if (status)
> + goto err;
> +err:
> + platform_device_put(evm_led_dev);
> + evm_led_dev = NULL;
Please look again at the above change very closely. You will want to
send an updated patch.
--
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTC broadband for 0.8mile line in suburbia: sync at 12.1Mbps down 622kbps up
According to speedtest.net: 11.9Mbps down 500kbps up
On Fri, Dec 27, 2019 at 04:01:42PM +0000, Russell King - ARM Linux admin wrote:
> On Fri, Dec 27, 2019 at 10:39:21AM +0800, Gen Zhang wrote:
> > In evm_led_setup(), the allocation result of platform_device_alloc() and
> > platform_device_add_data() should be checked.
> >
> > Signed-off-by: Gen Zhang <[email protected]>
> > ---
> > diff --git a/arch/arm/mach-davinci/board-dm644x-evm.c b/arch/arm/mach-davinci/board-dm644x-evm.c
> > index 9d87d4e..9cd2785 100644
> > --- a/arch/arm/mach-davinci/board-dm644x-evm.c
> > +++ b/arch/arm/mach-davinci/board-dm644x-evm.c
> > @@ -352,15 +352,20 @@ evm_led_setup(struct i2c_client *client, int gpio, unsigned ngpio, void *c)
> > * device unregistration ...
> > */
> > evm_led_dev = platform_device_alloc("leds-gpio", 0);
> > - platform_device_add_data(evm_led_dev,
> > + if (!evm_led_dev)
> > + return -ENOMEM;
> > + status = platform_device_add_data(evm_led_dev,
> > &evm_led_data, sizeof evm_led_data);
> > + if (status)
> > + goto err;
> >
> > evm_led_dev->dev.parent = &client->dev;
> > status = platform_device_add(evm_led_dev);
> > - if (status < 0) {
> > - platform_device_put(evm_led_dev);
> > - evm_led_dev = NULL;
> > - }
> > + if (status)
> > + goto err;
> > +err:
> > + platform_device_put(evm_led_dev);
> > + evm_led_dev = NULL;
>
> Please look again at the above change very closely. You will want to
> send an updated patch.
>
> --
> RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
> FTTC broadband for 0.8mile line in suburbia: sync at 12.1Mbps down 622kbps up
> According to speedtest.net: 11.9Mbps down 500kbps up
Thanks for your reply. You mean the if (state < 0 ) to if (state) or
anything else? Please point out directly.
Best,
Gen
On Sat, Dec 28, 2019 at 09:19:30PM +0800, Gen Zhang wrote:
> On Fri, Dec 27, 2019 at 04:01:42PM +0000, Russell King - ARM Linux admin wrote:
> > On Fri, Dec 27, 2019 at 10:39:21AM +0800, Gen Zhang wrote:
> > > In evm_led_setup(), the allocation result of platform_device_alloc() and
> > > platform_device_add_data() should be checked.
> > >
> > > Signed-off-by: Gen Zhang <[email protected]>
> > > ---
> > > diff --git a/arch/arm/mach-davinci/board-dm644x-evm.c b/arch/arm/mach-davinci/board-dm644x-evm.c
> > > index 9d87d4e..9cd2785 100644
> > > --- a/arch/arm/mach-davinci/board-dm644x-evm.c
> > > +++ b/arch/arm/mach-davinci/board-dm644x-evm.c
> > > @@ -352,15 +352,20 @@ evm_led_setup(struct i2c_client *client, int gpio, unsigned ngpio, void *c)
> > > * device unregistration ...
> > > */
> > > evm_led_dev = platform_device_alloc("leds-gpio", 0);
> > > - platform_device_add_data(evm_led_dev,
> > > + if (!evm_led_dev)
> > > + return -ENOMEM;
> > > + status = platform_device_add_data(evm_led_dev,
> > > &evm_led_data, sizeof evm_led_data);
> > > + if (status)
> > > + goto err;
> > >
> > > evm_led_dev->dev.parent = &client->dev;
> > > status = platform_device_add(evm_led_dev);
> > > - if (status < 0) {
> > > - platform_device_put(evm_led_dev);
> > > - evm_led_dev = NULL;
> > > - }
> > > + if (status)
> > > + goto err;
> > > +err:
> > > + platform_device_put(evm_led_dev);
> > > + evm_led_dev = NULL;
> >
> > Please look again at the above change very closely. You will want to
> > send an updated patch.
> >
> > --
> > RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
> > FTTC broadband for 0.8mile line in suburbia: sync at 12.1Mbps down 622kbps up
> > According to speedtest.net: 11.9Mbps down 500kbps up
>
> Thanks for your reply. You mean the if (state < 0 ) to if (state) or
> anything else? Please point out directly.
This is the old everything-successful path through the code:
platform_device_alloc()
platform_device_add_data()
platform_device_add()
evm_led_dev is set to the device
This is the new everything-successful path through the code:
platform_device_alloc()
platform_device_add_data()
platform_device_add()
platform_device_put()
evm_led_dev = NULL
And, specifically, the code sequence (I quote from your patch):
if (status)
goto err;
err:
is very stupid; it might as well not exist at all.
Since other code references evm_led_dev, one can assume that we do
not want it to be NULL for the success path. So, taking all this
together, your patch is very very wrong, and I also find it very
worrying too.
--
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTC broadband for 0.8mile line in suburbia: sync at 12.1Mbps down 622kbps up
According to speedtest.net: 11.9Mbps down 500kbps up
On Sat, Dec 28, 2019 at 01:48:24PM +0000, Russell King - ARM Linux admin wrote:
> This is the old everything-successful path through the code:
>
> platform_device_alloc()
> platform_device_add_data()
> platform_device_add()
> evm_led_dev is set to the device
>
> This is the new everything-successful path through the code:
>
> platform_device_alloc()
> platform_device_add_data()
> platform_device_add()
> platform_device_put()
> evm_led_dev = NULL
Thanks for your reply. Adding a return may handle this.
successful path:
platform_device_alloc()
platform_device_add_data()
platform_device_add()
return status
error path:
platform_device_put()
evm_led_dev = NULL
return status
correct?
>
> And, specifically, the code sequence (I quote from your patch):
>
> if (status)
> goto err;
> err:
>
> is very stupid; it might as well not exist at all.
Well, you have to admit that the result of platform_device_alloc(),
platform_device_add_data() and platform_device_add() should be checked,
and error should be handled.
e.g., there are 124 call sites of platform_device_add_data() in Linux. Only 24
are not checked, and most of them are in arm subsystem.
Look forward to deeper discussion of this problem.
Best,
Gen
>
> Since other code references evm_led_dev, one can assume that we do
> not want it to be NULL for the success path. So, taking all this
> together, your patch is very very wrong, and I also find it very
> worrying too.
>
> --
> RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
> FTTC broadband for 0.8mile line in suburbia: sync at 12.1Mbps down 622kbps up
> According to speedtest.net: 11.9Mbps down 500kbps up