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Date: Thu, 23 Nov 2006 12:06:48 +0100
Message-ID: <s5h8xi2h16f.wl%tiwai@suse.de>
From: Takashi Iwai <tiwai@suse.de>
To: Akinobu Mita <akinobu.mita@gmail.com>
Cc: linux-kernel@vger.kernel.org, Jaroslav Kysela <perex@suse.cz>
Subject: Re: [PATCH] sound: fix PCM substream list
In-Reply-To: <20061122185145.GF2985@APFDCB5C>
References: <20061122185145.GF2985@APFDCB5C>
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At Thu, 23 Nov 2006 03:51:45 +0900,
Akinobu Mita wrote:
> 
> If snd_pcm_new_stream() fails to initalize a substream (if
> snd_pcm_substream_proc_init() returns error), snd_pcm_new_stream()
> immediately return without unlinking that kfree()d substram.
> 
> It causes oops when snd_pcm_free() iterates the list of substream to
> free them by invalid reference.
> 
> Cc: Takashi Iwai <tiwai@suse.de>
> Cc: Jaroslav Kysela <perex@suse.cz>
> Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>

Merged this one to ALSA tree, too.
Thanks.


Takashi

> 
> ---
>  sound/core/pcm.c |    4 ++++
>  1 file changed, 4 insertions(+)
> 
> Index: work-fault-inject/sound/core/pcm.c
> ===================================================================
> --- work-fault-inject.orig/sound/core/pcm.c
> +++ work-fault-inject/sound/core/pcm.c
> @@ -638,6 +638,10 @@ int snd_pcm_new_stream(struct snd_pcm *p
>  		err = snd_pcm_substream_proc_init(substream);
>  		if (err < 0) {
>  			snd_printk(KERN_ERR "Error in snd_pcm_stream_proc_init\n");
> +			if (prev == NULL)
> +				pstr->substream = NULL;
> +			else
> +				prev->next = NULL;
>  			kfree(substream);
>  			return err;
>  		}
>