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Subject: Re: [PATCH] firmware_loader: Fix use-after-free Read in
 firmware_loading_store
To:     Luis Chamberlain <mcgrof@kernel.org>,
        Anirudh Rayabharam <mail@anirudhrb.com>
Cc:     Hillf Danton <hdanton@sina.com>, gregkh@linuxfoundation.org,
        rafael@kernel.org, linux-kernel@vger.kernel.org,
        syzbot+77cea49e091776a57689@syzkaller.appspotmail.com,
        Shuah Khan <skhan@linuxfoundation.org>
References: <20210708031321.50800-1-skhan@linuxfoundation.org>
 <20210709091721.1869-1-hdanton@sina.com>
 <d851dd11-1b4f-4ed2-bad2-0c267e3d6021@linuxfoundation.org>
 <3eb42554-c054-6e46-54ce-b9f637b72751@linuxfoundation.org>
 <20210715222817.tjsotu7fuhwz37ki@garbanzo>
From:   Shuah Khan <skhan@linuxfoundation.org>
Message-ID: <d17eeb0f-a46e-2515-43a6-36c16002928a@linuxfoundation.org>
Date:   Thu, 15 Jul 2021 16:46:24 -0600
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On 7/15/21 4:28 PM, Luis Chamberlain wrote:
> On Fri, Jul 09, 2021 at 10:38:12AM -0600, Shuah Khan wrote:
>> However I am seeing the following over and over again in the
>> log - hence I think it is safer to check the aborted status
>> in __fw_load_abort().
>>
>> ? __list_del_entry_valid+0xe0/0xf0
>> [  348.604808][T12994]  __list_del_entry_valid+0xe0/0xf0
>> [  348.610020][T12994]  firmware_loading_store+0x141/0x650
>> [  348.615761][T12994]  ? firmware_data_write+0x4e0/0x4e0
>> [  348.621064][T12994]  ? sysfs_file_ops+0x1c0/0x1c0
>> [  348.625921][T12994]  dev_attr_store+0x50/0x80
>>
>> Also the fallback logic takes actions based on errors as in
>> fw_load_sysfs_fallback() that returns -EAGAIN which would
>> trigger request_firmware() again.
>>
>> Based on all of this I think this fix is needed, if only I can
>> test for sure.
> 
> Shuah, curious if you had read this patch from Anirudh Rayabharam
> and my response to that v4 patch iteration?
> 
> https://lkml.kernel.org/r/20210518155921.4181-1-mail@anirudhrb.com
> 

Yes. I realized I am trying to fix the same problem we have been
discussing. :) Sorry for the noise.

Ignore my patch. I will follow the thread.

thanks,
-- Shuah