[PATCH] hwrng: cctrng: fix usage_count leak when autosuspend_delay is negative

[PATCH] hwrng: cctrng: fix usage_count leak when autosuspend_delay is negative

[Guangshuo Li]

cc_trng_pm_init() calls pm_runtime_use_autosuspend(), but
cc_trng_pm_fini() does not call the matching
pm_runtime_dont_use_autosuspend() before disabling runtime PM.

If the autosuspend delay is set to a negative value while autosuspend
is enabled, the runtime PM core increments usage_count to prevent
runtime suspend. Without calling pm_runtime_dont_use_autosuspend()
during teardown, this reference is not dropped and usage_count remains
unbalanced.

Add the missing pm_runtime_dont_use_autosuspend() call before disabling
runtime PM.

This issue was found by manual code inspection.

Fixes: a583ed310bb6 ("hwrng: cctrng - introduce Arm CryptoCell driver")
Cc: stable@vger.kernel.org
Signed-off-by: Guangshuo Li <lgs201920130244@gmail.com>
---
 drivers/char/hw_random/cctrng.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/char/hw_random/cctrng.c b/drivers/char/hw_random/cctrng.c
index a5be9258037f..bed4b9876d09 100644
--- a/drivers/char/hw_random/cctrng.c
+++ b/drivers/char/hw_random/cctrng.c
@@ -126,6 +126,7 @@ static void cc_trng_pm_fini(struct cctrng_drvdata *drvdata)
 {
 	struct device *dev = &(drvdata->pdev->dev);
 
+	pm_runtime_dont_use_autosuspend(dev);
 	pm_runtime_disable(dev);
 }
 
-- 
2.43.0

Re: [PATCH] hwrng: cctrng: fix usage_count leak when autosuspend_delay is negative

[Krzysztof Kozlowski]

On 08/08/2026 08:41, Guangshuo Li wrote:
> cc_trng_pm_init() calls pm_runtime_use_autosuspend(), but
> cc_trng_pm_fini() does not call the matching
> pm_runtime_dont_use_autosuspend() before disabling runtime PM.
> 
> If the autosuspend delay is set to a negative value while autosuspend
> is enabled, the runtime PM core increments usage_count to prevent
> runtime suspend. Without calling pm_runtime_dont_use_autosuspend()
> during teardown, this reference is not dropped and usage_count remains
> unbalanced.
> 
> Add the missing pm_runtime_dont_use_autosuspend() call before disabling
> runtime PM.
> 
> This issue was found by manual code inspection.
> 
> Fixes: a583ed310bb6 ("hwrng: cctrng - introduce Arm CryptoCell driver")
> Cc: stable@vger.kernel.org
> Signed-off-by: Guangshuo Li <lgs201920130244@gmail.com>

You sent vast amount of patches, all separate, making it very difficult
to track and respond in efficient way. Do not do that.

Group your work per subsystem.

You were asked to clarify and respond to incorrect fixes statement. I do
not see how you clarified and responded at all.

Best regards,
Krzysztof

Re: [PATCH] hwrng: cctrng: fix usage_count leak when autosuspend_delay is negative

[Guangshuo Li]

Hi Krzysztof,

On Thu, 20 Aug 2026 at 22:48, Krzysztof Kozlowski <krzk@kernel.org> wrote:
>
> On 08/08/2026 08:41, Guangshuo Li wrote:
> > cc_trng_pm_init() calls pm_runtime_use_autosuspend(), but
> > cc_trng_pm_fini() does not call the matching
> > pm_runtime_dont_use_autosuspend() before disabling runtime PM.
> >
> > If the autosuspend delay is set to a negative value while autosuspend
> > is enabled, the runtime PM core increments usage_count to prevent
> > runtime suspend. Without calling pm_runtime_dont_use_autosuspend()
> > during teardown, this reference is not dropped and usage_count remains
> > unbalanced.
> >
> > Add the missing pm_runtime_dont_use_autosuspend() call before disabling
> > runtime PM.
> >
> > This issue was found by manual code inspection.
> >
> > Fixes: a583ed310bb6 ("hwrng: cctrng - introduce Arm CryptoCell driver")
> > Cc: stable@vger.kernel.org
> > Signed-off-by: Guangshuo Li <lgs201920130244@gmail.com>
>
> You sent vast amount of patches, all separate, making it very difficult
> to track and respond in efficient way. Do not do that.
>
> Group your work per subsystem.
>
> You were asked to clarify and respond to incorrect fixes statement. I do
> not see how you clarified and responded at all.
>
> Best regards,
> Krzysztof

Sorry about that. I should have replied to the earlier review comments
explicitly, and I also should not have sent so many separate patches.

I will group future patches by subsystem and make sure to respond
clearly to review feedback before resending.

Thanks for pointing this out.

Best regards,
Guangshuo