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From: Thomas Gleixner <tglx@linutronix.de>
To: "chenjun (AM)" <chenjun102@huawei.com>, "linux-kernel@vger.kernel.org"
 <linux-kernel@vger.kernel.org>
Cc: "xuqiang (M)" <xuqiang36@huawei.com>
Subject: Re: [PATCH] irqchip/mbigen: Fix incorrect null pointer check
In-Reply-To: <45fe193a87fc4a5cb2e3233386b47dc7@huawei.com>
References: <20240129130003.18181-1-chenjun102@huawei.com>
 <874jecisku.ffs@tglx> <45fe193a87fc4a5cb2e3233386b47dc7@huawei.com>
Date: Sun, 18 Feb 2024 20:58:44 +0100
Message-ID: <87a5nxbl3f.ffs@tglx>
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On Sun, Feb 18 2024 at 03:13, chenjun (AM) wrote:
> =E5=9C=A8 2024/2/13 18:09, Thomas Gleixner =E5=86=99=E9=81=93:
>> On Mon, Jan 29 2024 at 21:00, Chen Jun wrote:
>>=20
>> That's not about an incorrect NULL pointer check. That's about using a
>> function which is guaranteed to return NULL on your platform, no?
>>=20
>>> bus_get_dev_root(&platform_bus_type) always returns NULL.
>>=20
>> Lacks an explanation why this always returns NULL.
>>=20
>
> Thank you for the reply.
>
> bus_get_dev_root returns sp->dev_root set in subsys_register.
> And subsys_register is not called by platform_bus_init.
>
> So, for platform_bus_type, bus_get_dev_root always returns NULL.

Please add this information to the change log.

Thanks,

        tglx