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From: "Ze Huang" <huang.ze@linux.dev>
To: "Linus Walleij" <linusw@kernel.org>,
	"Jiayu Du" <jiayu.riscv@isrc.iscas.ac.cn>
Cc: <pjw@kernel.org>, <palmer@dabbelt.com>, <aou@eecs.berkeley.edu>,
	<alex@ghiti.fr>, <linux-gpio@vger.kernel.org>,
	<linux-riscv@lists.infradead.org>, <linux-kernel@vger.kernel.org>,
	<gaohan@iscas.ac.cn>, <me@ziyao.cc>
Subject: Re: [PATCH v2] pinctrl: canaan: k230: Fix NULL pointer dereference when parsing devicetree
Date: Tue, 03 Feb 2026 22:02:33 +0800	[thread overview]
Message-ID: <DG5DRZU7IUOE.38JEHK3H9ICCV@linux.dev> (raw)
In-Reply-To: <CAD++jL=Up=y_pX4Xy50in08cT978ANaoiD_98nn99frb8=5vOA@mail.gmail.com>

On Tue Feb 3, 2026 at 8:32 AM CST, Linus Walleij wrote:
> On Sun, Dec 28, 2025 at 4:53 PM Jiayu Du <jiayu.riscv@isrc.iscas.ac.cn> wrote:
>
>> When probing the k230 pinctrl driver, the kernel triggers a NULL pointer
>> dereference. The crash trace showed:
>> [    0.732084] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000068
>> [    0.740737] ...
>> [    0.776296] epc : k230_pinctrl_probe+0x1be/0x4fc
>>
>> In k230_pinctrl_parse_functions(), we attempt to retrieve the device
>> pointer via info->pctl_dev->dev, but info->pctl_dev is only initialized
>> after k230_pinctrl_parse_dt() completes.
>>
>> At the time of DT parsing, info->pctl_dev is still NULL, leading to
>> the invalid dereference of info->pctl_dev->dev.
>>
>> Use the already available device pointer from platform_device
>> instead of accessing through uninitialized pctl_dev.
>>
>> Fixes: d94a32ac688f ("pinctrl: canaan: k230: Fix order of DT parse and pinctrl register")
>> Signed-off-by: Jiayu Du <jiayu.riscv@isrc.iscas.ac.cn>
>
> Patch applied!
>
> Sorry for missing this, I was waiting for maintainer feedback
> but it never arrived.
>
> Yours,
> Linus Walleij

Hi Linus, Jiayu,

Apologies for the delay.

I tested this on k230; it fixes the NULL pointer dereference during pinctrl
probing. The approach is correct.

Thanks to you both!

Best regards, Ze Huang

WARNING: multiple messages have this Message-ID (diff)
From: "Ze Huang" <huang.ze@linux.dev>
To: "Linus Walleij" <linusw@kernel.org>,
	"Jiayu Du" <jiayu.riscv@isrc.iscas.ac.cn>
Cc: <pjw@kernel.org>, <palmer@dabbelt.com>, <aou@eecs.berkeley.edu>,
	<alex@ghiti.fr>, <linux-gpio@vger.kernel.org>,
	<linux-riscv@lists.infradead.org>, <linux-kernel@vger.kernel.org>,
	<gaohan@iscas.ac.cn>, <me@ziyao.cc>
Subject: Re: [PATCH v2] pinctrl: canaan: k230: Fix NULL pointer dereference when parsing devicetree
Date: Tue, 03 Feb 2026 22:02:33 +0800	[thread overview]
Message-ID: <DG5DRZU7IUOE.38JEHK3H9ICCV@linux.dev> (raw)
In-Reply-To: <CAD++jL=Up=y_pX4Xy50in08cT978ANaoiD_98nn99frb8=5vOA@mail.gmail.com>

On Tue Feb 3, 2026 at 8:32 AM CST, Linus Walleij wrote:
> On Sun, Dec 28, 2025 at 4:53 PM Jiayu Du <jiayu.riscv@isrc.iscas.ac.cn> wrote:
>
>> When probing the k230 pinctrl driver, the kernel triggers a NULL pointer
>> dereference. The crash trace showed:
>> [    0.732084] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000068
>> [    0.740737] ...
>> [    0.776296] epc : k230_pinctrl_probe+0x1be/0x4fc
>>
>> In k230_pinctrl_parse_functions(), we attempt to retrieve the device
>> pointer via info->pctl_dev->dev, but info->pctl_dev is only initialized
>> after k230_pinctrl_parse_dt() completes.
>>
>> At the time of DT parsing, info->pctl_dev is still NULL, leading to
>> the invalid dereference of info->pctl_dev->dev.
>>
>> Use the already available device pointer from platform_device
>> instead of accessing through uninitialized pctl_dev.
>>
>> Fixes: d94a32ac688f ("pinctrl: canaan: k230: Fix order of DT parse and pinctrl register")
>> Signed-off-by: Jiayu Du <jiayu.riscv@isrc.iscas.ac.cn>
>
> Patch applied!
>
> Sorry for missing this, I was waiting for maintainer feedback
> but it never arrived.
>
> Yours,
> Linus Walleij

Hi Linus, Jiayu,

Apologies for the delay.

I tested this on k230; it fixes the NULL pointer dereference during pinctrl
probing. The approach is correct.

Thanks to you both!

Best regards, Ze Huang

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  reply	other threads:[~2026-02-03 14:03 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-12-28 15:49 [PATCH v2] pinctrl: canaan: k230: Fix NULL pointer dereference when parsing devicetree Jiayu Du
2025-12-28 15:49 ` Jiayu Du
2026-01-15  6:38 ` Jiayu Du
2026-01-15  6:38   ` Jiayu Du
2026-01-20  6:03   ` Jiayu Du
2026-01-20  6:03     ` Jiayu Du
2026-02-03  0:32 ` Linus Walleij
2026-02-03  0:32   ` Linus Walleij
2026-02-03 14:02   ` Ze Huang [this message]
2026-02-03 14:02     ` Ze Huang

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