Re: [PATCH] ALSA: usx2y: fix a memory leak bug

[Takashi Iwai <tiwai@suse.de>]

On Sun, 28 Apr 2019 09:18:40 +0200,
Takashi Iwai wrote:
> 
> On Sun, 28 Apr 2019 08:42:32 +0200,
> Wenwen Wang wrote:
> > 
> > In usX2Y_In04_init(), a new urb is firstly created through usb_alloc_urb()
> > and saved to 'usX2Y->In04urb'. Then, a buffer is allocated through
> > kmalloc() and saved to 'usX2Y->In04Buf'. After the urb is initialized, a
> > sanity check is performed for the endpoint in the urb by invoking
> > usb_urb_ep_type_check(). If the check fails, the error code EINVAL will be
> > returned. In that case, however, the created urb and the allocated buffer
> > are not freed, leading to memory leaks.
> > 
> > To fix the above issue, free the urb and the buffer if the check fails.
> > 
> > Signed-off-by: Wenwen Wang <wang6495@umn.edu>
> 
> Applied now, thanks.

... and looking at the code again, this patch turned out to be wrong.
The in04 urb and transfer buffer are freed at card->private_free
callback (snd_usX2Y_card_private_free()) later, so this patch would
lead to double-free.

I dropped the patch now.


thanks,

Takashi