[PATCH] powerpc/warp: Fix error handling in pika_dtm_thread

[PATCH] powerpc/warp: Fix error handling in pika_dtm_thread

[Ma Ke]

pika_dtm_thread() acquires client through of_find_i2c_device_by_node()
but fails to release it in error handling path. This could result in a
reference count leak, preventing proper cleanup and potentially
leading to resource exhaustion. Add put_device() to release the
reference in the error handling path.

Found by code review.

Cc: stable@vger.kernel.org
Fixes: 3984114f0562 ("powerpc/warp: Platform fix for i2c change")
Signed-off-by: Ma Ke <make24@iscas.ac.cn>
---
 arch/powerpc/platforms/44x/warp.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/powerpc/platforms/44x/warp.c b/arch/powerpc/platforms/44x/warp.c
index a5001d32f978..6f674f86dc85 100644
--- a/arch/powerpc/platforms/44x/warp.c
+++ b/arch/powerpc/platforms/44x/warp.c
@@ -293,6 +293,8 @@ static int pika_dtm_thread(void __iomem *fpga)
 		schedule_timeout(HZ);
 	}
 
+	put_device(&client->dev);
+
 	return 0;
 }
 
-- 
2.17.1

Re: [PATCH] powerpc/warp: Fix error handling in pika_dtm_thread

[Christophe Leroy]

Le 16/11/2025 à 03:44, Ma Ke a écrit :
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> 
> pika_dtm_thread() acquires client through of_find_i2c_device_by_node()
> but fails to release it in error handling path. This could result in a
> reference count leak, preventing proper cleanup and potentially
> leading to resource exhaustion. Add put_device() to release the
> reference in the error handling path.

It is not really an error path, it is the termination of the kthread.

> 
> Found by code review.
> 
> Cc: stable@vger.kernel.org
> Fixes: 3984114f0562 ("powerpc/warp: Platform fix for i2c change")
> Signed-off-by: Ma Ke <make24@iscas.ac.cn>

Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>

> ---
>   arch/powerpc/platforms/44x/warp.c | 2 ++
>   1 file changed, 2 insertions(+)
> 
> diff --git a/arch/powerpc/platforms/44x/warp.c b/arch/powerpc/platforms/44x/warp.c
> index a5001d32f978..6f674f86dc85 100644
> --- a/arch/powerpc/platforms/44x/warp.c
> +++ b/arch/powerpc/platforms/44x/warp.c
> @@ -293,6 +293,8 @@ static int pika_dtm_thread(void __iomem *fpga)
>                  schedule_timeout(HZ);
>          }
> 
> +       put_device(&client->dev);
> +
>          return 0;
>   }
> 
> --
> 2.17.1
> 

Re: [PATCH] powerpc/warp: Fix error handling in pika_dtm_thread

[Madhavan Srinivasan]

On Sun, 16 Nov 2025 10:44:11 +0800, Ma Ke wrote:
> pika_dtm_thread() acquires client through of_find_i2c_device_by_node()
> but fails to release it in error handling path. This could result in a
> reference count leak, preventing proper cleanup and potentially
> leading to resource exhaustion. Add put_device() to release the
> reference in the error handling path.
> 
> Found by code review.
> 
> [...]

Applied to powerpc/fixes.

[1/1] powerpc/warp: Fix error handling in pika_dtm_thread
      https://git.kernel.org/powerpc/c/108d7f951271cbd36ca36efc5e5d106966f5180c

cheers