[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <a258b613-3697-4f21-a8fd-20b276f63132@gmail.com>
Date: Sat, 18 May 2024 02:10:44 +0900
From: Yunseong Kim <yskelg@...il.com>
To: Takashi Iwai <tiwai@...e.de>
Cc: Jaroslav Kysela <perex@...ex.cz>, skhan@...uxfoundation.org,
Bjorn Helgaas <helgaas@...nel.org>,
linux-kernel-mentees@...ts.linuxfoundation.org,
Austin Kim <austindh.kim@...il.com>, shjy180909@...il.com,
linux-sound@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] line6: add midibuf init failure handling in
line6_init_midi()
On 5/17/24 5:32 오후, Takashi Iwai wrote:
> The allocated object is already freed by snd_line6_midi_free() that is
> called via rawmidi private_free at its destruction. So your change
> would lead to a double-free.
>
>
> thanks,
>
> Takashi
Thanks for the review Takashi.
I have one question:
line6_midibuf_destroy() have no NULL check for the memory to free.
If line6midi->midibuf_in is in this->buf = NULL from
line6_midibuf_init() with memory allocation failed,
won't the free(NULL) when accessed by snd_line6_midi_free() to
line6_midibuf_destroy()?
In the first patch, I was making a misunderstanding
Now that you mention it, I can see where it's freeing!
It helped me a lot in analyzing the driver code.
Please let me know if I've misunderstood anything.
Warm Regards,
Yunseong Kim
>> ---
>> sound/usb/line6/midi.c | 9 +++++++--
>> 1 file changed, 7 insertions(+), 2 deletions(-)
>>
>> diff --git a/sound/usb/line6/midi.c b/sound/usb/line6/midi.c
>> index 0838632c788e..abcf58f46673 100644
>> --- a/sound/usb/line6/midi.c
>> +++ b/sound/usb/line6/midi.c
>> @@ -283,13 +283,18 @@ int line6_init_midi(struct usb_line6 *line6)
>>
>> err = line6_midibuf_init(&line6midi->midibuf_in, MIDI_BUFFER_SIZE, 0);
>> if (err < 0)
>> - return err;
>> + goto error;
>>
>> err = line6_midibuf_init(&line6midi->midibuf_out, MIDI_BUFFER_SIZE, 1);
>> if (err < 0)
>> - return err;
>> + goto error;
>>
>> line6->line6midi = line6midi;
>> return 0;
>> +
>> +error:
>> + kfree(line6midi);
>> + return err;
>> +
>> }
>> EXPORT_SYMBOL_GPL(line6_init_midi);
>> --
>> 2.34.1
>>
Powered by blists - more mailing lists