linux-kernel - Re: [PATCH] module: Fix NULL vs IS_ERR checking for module_get_next

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Message-ID: <130cbc98-ef82-027e-d610-4273756d36ba@gmail.com>
Date:   Thu, 10 Nov 2022 14:26:35 +0800
From:   Miaoqian Lin <linmq006@...il.com>
To:     Luis Chamberlain <mcgrof@...nel.org>
Cc:     Dmitry Torokhov <dmitry.torokhov@...il.com>,
        linux-modules@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] module: Fix NULL vs IS_ERR checking for
 module_get_next_page


On 2022/11/10 14:05, Luis Chamberlain wrote:
> On Thu, Nov 10, 2022 at 12:18:50PM +0800, Miaoqian Lin wrote:
>> Hi,
>>
>> On 2022/11/10 12:09, Luis Chamberlain wrote:
>>> On Thu, Nov 10, 2022 at 06:58:34AM +0400, Miaoqian Lin wrote:
>>>> The module_get_next_page() function return error pointers on error
>>>> instead of NULL.
>>>> Use IS_ERR() to check the return value to fix this.
>>>>
>>>> Fixes: b1ae6dc41eaa ("module: add in-kernel support for decompressing")
>>>> Signed-off-by: Miaoqian Lin <linmq006@...il.com>
>>>> ---
>>> Thanks queued up. How did you find out? Just code inspection? I see
>>> chances are low of this triggering, but just curious how you found it.
>> I found this by static analysis, specifically, I obtained functions that return error pointers and
>> inspected whether their callers followed the correct specification.
> Which one did you use?
I wrote custom checker based on the weggli tool (https://github.com/googleprojectzero/weggli).
>   Luis