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[PATCH] parisc: led: fix reference leak on failed device registration

Guangshuo Li posted 1 patch 2 months ago 
drivers/parisc/led.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
[PATCH] parisc: led: fix reference leak on failed device registration
Posted by Guangshuo Li 2 months ago 
When platform_device_register() fails in startup_leds(), the embedded
struct device in platform_leds has already been initialized by
device_initialize(), but the failure path only reports the error and
does not drop the device reference for the current platform device:

  startup_leds()
    -> platform_device_register(&platform_leds)
       -> device_initialize(&platform_leds.dev)
       -> setup_pdev_dma_masks(&platform_leds)
       -> platform_device_add(&platform_leds)

This leads to a reference leak when platform_device_register() fails.
Fix this by calling platform_device_put() after reporting the error.

The issue was identified by a static analysis tool I developed and
confirmed by manual review.

Fixes: 789e527adfc33 ("parisc: led: Rewrite LED/LCD driver to utilizize Linux LED subsystem")
Cc: stable@vger.kernel.org
Signed-off-by: Guangshuo Li <lgs201920130244@gmail.com>
---
 drivers/parisc/led.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/parisc/led.c b/drivers/parisc/led.c
index 016c9d5a60a8..b299fcc48b08 100644
--- a/drivers/parisc/led.c
+++ b/drivers/parisc/led.c
@@ -543,8 +543,10 @@ static void __init register_led_regions(void)
 
 static int __init startup_leds(void)
 {
-	if (platform_device_register(&platform_leds))
-                printk(KERN_INFO "LED: failed to register LEDs\n");
+	if (platform_device_register(&platform_leds)) {
+		pr_info("LED: failed to register LEDs\n");
+		platform_device_put(&platform_leds);
+	}
 	register_led_regions();
 	return 0;
 }
-- 
2.43.0
Re: [PATCH] parisc: led: fix reference leak on failed device registration
Posted by Helge Deller 2 months ago 
On 4/15/26 19:05, Guangshuo Li wrote:
> When platform_device_register() fails in startup_leds(), the embedded
> struct device in platform_leds has already been initialized by
> device_initialize(), but the failure path only reports the error and
> does not drop the device reference for the current platform device:
> 
>    startup_leds()
>      -> platform_device_register(&platform_leds)
>         -> device_initialize(&platform_leds.dev)
>         -> setup_pdev_dma_masks(&platform_leds)
>         -> platform_device_add(&platform_leds)
> 
> This leads to a reference leak when platform_device_register() fails.
> Fix this by calling platform_device_put() after reporting the error.
> 
> The issue was identified by a static analysis tool I developed and
> confirmed by manual review.
> 
> Fixes: 789e527adfc33 ("parisc: led: Rewrite LED/LCD driver to utilizize Linux LED subsystem")
> Cc: stable@vger.kernel.org
> Signed-off-by: Guangshuo Li <lgs201920130244@gmail.com>
> ---
>   drivers/parisc/led.c | 6 ++++--
>   1 file changed, 4 insertions(+), 2 deletions(-)

applied.
Thanks!
Helge
Re: [PATCH] parisc: led: fix reference leak on failed device registration
Posted by Jiri Slaby 1 month, 4 weeks ago 
On 17. 04. 26, 11:39, Helge Deller wrote:
> On 4/15/26 19:05, Guangshuo Li wrote:
>> When platform_device_register() fails in startup_leds(), the embedded
>> struct device in platform_leds has already been initialized by
>> device_initialize(), but the failure path only reports the error and
>> does not drop the device reference for the current platform device:
>>
>>    startup_leds()
>>      -> platform_device_register(&platform_leds)
>>         -> device_initialize(&platform_leds.dev)
>>         -> setup_pdev_dma_masks(&platform_leds)
>>         -> platform_device_add(&platform_leds)
>>
>> This leads to a reference leak when platform_device_register() fails.
>> Fix this by calling platform_device_put() after reporting the error.
>>
>> The issue was identified by a static analysis tool I developed and
>> confirmed by manual review.
>>
>> Fixes: 789e527adfc33 ("parisc: led: Rewrite LED/LCD driver to 
>> utilizize Linux LED subsystem")
>> Cc: stable@vger.kernel.org
>> Signed-off-by: Guangshuo Li <lgs201920130244@gmail.com>
>> ---
>>   drivers/parisc/led.c | 6 ++++--
>>   1 file changed, 4 insertions(+), 2 deletions(-)
> 
> applied.
> Thanks!
> Helge

Unless the static pcmtst_pdev has ->type->release or ->release set, the 
patch triggers a warning upon put().

platform_device_register() should be fixed instead.

See also:
https://patchew.org/linux/20260415174159.3625777-1-lgs201920130244@gmail.com/

thanks,
-- 
js
suse labs
Re: [PATCH] parisc: led: fix reference leak on failed device registration
Posted by Helge Deller 1 month, 4 weeks ago 
Hi Jiri,

On 4/23/26 07:24, Jiri Slaby wrote:
> On 17. 04. 26, 11:39, Helge Deller wrote:
>> On 4/15/26 19:05, Guangshuo Li wrote:
>>> When platform_device_register() fails in startup_leds(), the embedded
>>> struct device in platform_leds has already been initialized by
>>> device_initialize(), but the failure path only reports the error and
>>> does not drop the device reference for the current platform device:
>>>
>>>    startup_leds()
>>>      -> platform_device_register(&platform_leds)
>>>         -> device_initialize(&platform_leds.dev)
>>>         -> setup_pdev_dma_masks(&platform_leds)
>>>         -> platform_device_add(&platform_leds)
>>>
>>> This leads to a reference leak when platform_device_register() fails.
>>> Fix this by calling platform_device_put() after reporting the error.
>>>
>>> The issue was identified by a static analysis tool I developed and
>>> confirmed by manual review.
>>>
>>> Fixes: 789e527adfc33 ("parisc: led: Rewrite LED/LCD driver to utilizize Linux LED subsystem")
>>> Cc: stable@vger.kernel.org
>>> Signed-off-by: Guangshuo Li <lgs201920130244@gmail.com>
>>> ---
>>>   drivers/parisc/led.c | 6 ++++--
>>>   1 file changed, 4 insertions(+), 2 deletions(-)
>>
>> applied.
>> Thanks!
>> Helge
> 
> Unless the static pcmtst_pdev has ->type->release or ->release set, the patch triggers a warning upon put().
> 
> platform_device_register() should be fixed instead.

Thanks for the notice! I'm going to revert that patch.

Just yesterday I refused to apply the other patches for fbdev and suggested
to fix platform_device_register() instead. See:
https://marc.info/?l=linux-fbdev&m=177687117206684&w=2

> See also:
> https://patchew.org/linux/20260415174159.3625777-1-lgs201920130244@gmail.com/
Thanks!
Helge
Re: [PATCH] parisc: led: fix reference leak on failed device registration
Posted by Guangshuo Li 1 month, 3 weeks ago 
Hi Jiri, Helge,

Thanks for pointing this out, and thanks Helge for taking care of the
revert.

On Thu, 23 Apr 2026 at 15:09, Helge Deller <deller@gmx.de> wrote:
>
> Hi Jiri,
>
> On 4/23/26 07:24, Jiri Slaby wrote:
> > On 17. 04. 26, 11:39, Helge Deller wrote:
> >> On 4/15/26 19:05, Guangshuo Li wrote:
> >>> When platform_device_register() fails in startup_leds(), the embedded
> >>> struct device in platform_leds has already been initialized by
> >>> device_initialize(), but the failure path only reports the error and
> >>> does not drop the device reference for the current platform device:
> >>>
> >>>    startup_leds()
> >>>      -> platform_device_register(&platform_leds)
> >>>         -> device_initialize(&platform_leds.dev)
> >>>         -> setup_pdev_dma_masks(&platform_leds)
> >>>         -> platform_device_add(&platform_leds)
> >>>
> >>> This leads to a reference leak when platform_device_register() fails.
> >>> Fix this by calling platform_device_put() after reporting the error.
> >>>
> >>> The issue was identified by a static analysis tool I developed and
> >>> confirmed by manual review.
> >>>
> >>> Fixes: 789e527adfc33 ("parisc: led: Rewrite LED/LCD driver to utilizize Linux LED subsystem")
> >>> Cc: stable@vger.kernel.org
> >>> Signed-off-by: Guangshuo Li <lgs201920130244@gmail.com>
> >>> ---
> >>>   drivers/parisc/led.c | 6 ++++--
> >>>   1 file changed, 4 insertions(+), 2 deletions(-)
> >>
> >> applied.
> >> Thanks!
> >> Helge
> >
> > Unless the static pcmtst_pdev has ->type->release or ->release set, the patch triggers a warning upon put().
> >
> > platform_device_register() should be fixed instead.
>
> Thanks for the notice! I'm going to revert that patch.
>
> Just yesterday I refused to apply the other patches for fbdev and suggested
> to fix platform_device_register() instead. See:
> https://marc.info/?l=linux-fbdev&m=177687117206684&w=2
>
> > See also:
> > https://patchew.org/linux/20260415174159.3625777-1-lgs201920130244@gmail.com/
> Thanks!
> Helge

I agree that this patch is not appropriate. platform_leds is a static
platform_device and it does not provide a dev.release callback, so calling
platform_device_put() on the platform_device_register() failure path can
trigger the missing release callback warning.

Please disregard this patch. I will drop it, and I am also going through
the other patches I sent for the same pattern and following up where they
should be ignored or reverted.

Sorry for the noise.

Best regards,
Guangshuo Li

Patchew 2.1-devel-ea86937

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