MIME-Version: 1.0
References: <20211230051132.21056-1-hbh25y@gmail.com> <20211230051132.21056-3-hbh25y@gmail.com>
 <Yc4MeIt6JygZ6CrY@rowland.harvard.edu>
In-Reply-To: <Yc4MeIt6JygZ6CrY@rowland.harvard.edu>
From:   Hangyu Hua <hbh25y@gmail.com>
Date:   Fri, 31 Dec 2021 10:31:51 +0800
Message-ID: <CAOo-nLLpNfHzrOyF4P0XvFK1h+J+aZqGL+AqmZP2PG6C=rcFjg@mail.gmail.com>
Subject: Re: [PATCH v3 2/2] usb: gadget: clear related members when goto fail
To:     Alan Stern <stern@rowland.harvard.edu>
Cc:     balbi@kernel.org, gregkh@linuxfoundation.org, axboe@kernel.dk,
        jj251510319013@gmail.com, dan.carpenter@oracle.com,
        linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
Precedence: bulk

On 2021/12/31 =E4=B8=8A=E5=8D=883:46, Alan Stern wrote:
> You must not do this.  I never sent you an Acked-by for this patch; you
> shouldn't claim that I did.

I am sorry about this. I should read the linux kernel community rules
more carefully.

>>      value =3D usb_gadget_probe_driver(&gadgetfs_driver);
>>      if (value !=3D 0) {
>> +            dev->dev =3D NULL;
>> +            dev->hs_config =3D NULL;
>> +            dev->config =3D NULL;
>>              kfree (dev->buf);
>>              dev->buf =3D NULL;
> Why not just grep the lock and goto fail?

You are right. I will modify my patch later.

>>      } else {
>> @@ -1892,7 +1895,12 @@ dev_config (struct file *fd, const char __user *b=
uf, size_t len, loff_t *ptr)
>>      }
>>      return value;
>>
>> +fail2:
>> +    dev->dev =3D NULL;
>> +fail1:
>> +    dev->hs_config =3D NULL;
>
> It is not necessary to have all these different statement labels.  You
> can simply have "fail:" clear all three pointers.
>
>>   fail:
>> +    dev->config =3D NULL;
>>      spin_unlock_irq (&dev->lock);
>>      pr_debug ("%s: %s fail %zd, %p\n", shortname, __func__, value, dev)=
;
>>      kfree (dev->buf);
>
> Alan Stern
>

I don't think so. It is not necessary to clean all three pointers if
some of them aren't kbuf. I think it may be better to keep their own
pointers.

Thanks. Happy new year.