linux-kernel - Re: [PATCH] ALSA: pcm: fix a memory leak bug

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Message-ID: <s5h8ss5o569.wl-tiwai@suse.de>
Date:   Wed, 07 Aug 2019 08:33:50 +0200
From:   Takashi Iwai <tiwai@...e.de>
To:     Wenwen Wang <wenwen@...uga.edu>
Cc:     "moderated list:SOUND" <alsa-devel@...a-project.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Allison Randal <allison@...utok.net>,
        Jaroslav Kysela <perex@...ex.cz>,
        Takashi Iwai <tiwai@...e.com>,
        open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] ALSA: pcm: fix a memory leak bug

On Wed, 07 Aug 2019 08:15:17 +0200,
Wenwen Wang wrote:
> 
> In hiface_pcm_init(), 'rt' is firstly allocated through kzalloc(). Later
> on, hiface_pcm_init_urb() is invoked to initialize 'rt->out_urbs[i]'.
> However, if the initialization fails, 'rt' is not deallocated, leading to a
> memory leak bug.
> 
> To fix the above issue, free 'rt' before returning the error.
> 
> Signed-off-by: Wenwen Wang <wenwen@...uga.edu>
> ---
>  sound/usb/hiface/pcm.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/sound/usb/hiface/pcm.c b/sound/usb/hiface/pcm.c
> index 14fc1e1..5dbcd0d 100644
> --- a/sound/usb/hiface/pcm.c
> +++ b/sound/usb/hiface/pcm.c
> @@ -599,8 +599,10 @@ int hiface_pcm_init(struct hiface_chip *chip, u8
> extra_freq)
>         for (i = 0; i < PCM_N_URBS; i++) {
>                 ret = hiface_pcm_init_urb(&rt->out_urbs[i], chip, OUT_EP,
>                                     hiface_pcm_out_urb_handler);
> -               if (ret < 0)
> +               if (ret < 0) {
> +                       kfree(rt);
>                         return ret;
> +               }

Unfortunately this still leaves some memory.  We need to release
rt->out_urbs[], too.  The relevant code is already in
hiface_pcm_destroy(), so factor out the looped kfree() there and call
it from both places.

Care to resubmit with more fixes?


thanks,

Takashi