linux-kernel - Re: linux-next: build failure after merge of the pwm tree

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <22fl35khmbf6ufyjzbfvxor7b6nohqakqovjoya3v4mmlenz5c@6wbdednrd2pb>
Date: Mon, 27 Oct 2025 09:11:31 +0100
From: Uwe Kleine-König <ukleinek@...nel.org>
To: Stephen Rothwell <sfr@...b.auug.org.au>
Cc: Michal Wilczynski <m.wilczynski@...sung.com>, 
	Danilo Krummrich <dakr@...nel.org>, Boqun Feng <boqun.feng@...il.com>, 
	Daniel Almeida <daniel.almeida@...labora.com>, Peter Colberg <pcolberg@...hat.com>, 
	Lyude Paul <lyude@...hat.com>, Miguel Ojeda <ojeda@...nel.org>, 
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>, Linux Next Mailing List <linux-next@...r.kernel.org>, 
	Alice Ryhl <aliceryhl@...gle.com>, Viresh Kumar <viresh.kumar@...aro.org>, 
	Alexandre Courbot <acourbot@...dia.com>, Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Subject: Re: linux-next: build failure after merge of the pwm tree

Hello Stephen,

thanks for your report (and creating next each day!)

On Mon, Oct 27, 2025 at 12:51:48PM +1100, Stephen Rothwell wrote:
> After merging the pwm tree, today's linux-next build (x86_64 allmodconfig)
> failed like this:
> 
> error[E0277]: the trait bound `core::result::Result<core::pin::Pin<Box<Th1520PwmPlatformDriver, Kmalloc>>, kernel::error::Error>: PinInit<Th1520PwmPlatformDriver, kernel::error::Error>` is not satisfied
>    --> drivers/pwm/pwm_th1520.rs:331:10
>     |
> 331 |     ) -> Result<Pin<KBox<Self>>> {
>     |          ^^^^^^^^^^^^^^^^^^^^^^^ unsatisfied trait bound
>     |
>     = help: the trait `PinInit<Th1520PwmPlatformDriver, kernel::error::Error>` is not implemented for `Result<Pin<Box<Th1520PwmPlatformDriver, Kmalloc>>, Error>`
>             but trait `PinInit<core::pin::Pin<Box<Th1520PwmPlatformDriver, Kmalloc>>, kernel::error::Error>` is implemented for it
>     = help: for that trait implementation, expected `core::pin::Pin<Box<Th1520PwmPlatformDriver, Kmalloc>>`, found `Th1520PwmPlatformDriver`
> note: required by a bound in `kernel::platform::Driver::{synthetic#0}`
>    --> rust/kernel/platform.rs:196:15
>     |
> 196 |     ) -> impl PinInit<Self, Error>;
>     |               ^^^^^^^^^^^^^^^^^^^^ required by this bound in `Driver::{synthetic#0}`
> 
> error: aborting due to 1 previous error
> 
> For more information about this error, try `rustc --explain E0277`.
> 
> Caused by commit
> 
>   fb3957af9ec6 ("pwm: Add Rust driver for T-HEAD TH1520 SoC")
> 
> presumably interacting with something merged earlier in my tree.
> If someone could provide me with an appropriate merge resolution, I will
> apply it.

Having no relevant clue about Rust, I bisected that. The bisection points to
0242623384c7 ("rust: driver: let probe() return impl PinInit<Self, Error>").

Translating the changes that commit does to
drivers/gpu/drm/nova/driver.rs for drivers/pwm/pwm_th1520.rs results in:

diff --git a/drivers/pwm/pwm_th1520.rs b/drivers/pwm/pwm_th1520.rs
index 0ad38b78be85..dd554574adc8 100644
--- a/drivers/pwm/pwm_th1520.rs
+++ b/drivers/pwm/pwm_th1520.rs
@@ -328,7 +328,7 @@ impl platform::Driver for Th1520PwmPlatformDriver {
     fn probe(
         pdev: &platform::Device<Core>,
         _id_info: Option<&Self::IdInfo>,
-    ) -> Result<Pin<KBox<Self>>> {
+    ) -> impl PinInit<Self, Error> {
         let dev = pdev.as_ref();
         let request = pdev.io_request_by_index(0).ok_or(ENODEV)?;
 
@@ -365,7 +365,7 @@ fn probe(
 
         pwm::Registration::register(dev, chip)?;
 
-        Ok(KBox::new(Th1520PwmPlatformDriver, GFP_KERNEL)?.into())
+        Ok(Th1520PwmPlatformDriver)
     }
 }
 
which builds again.

Best regards
Uwe

Download attachment "signature.asc" of type "application/pgp-signature" (489 bytes)