4.4-stable review patch. If anyone has any objections, please let me know.
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From: Takashi Iwai tiwai@suse.de
commit f13876e2c33a657a71bcbb10f767c0951b165020 upstream.
Since snd_pcm_ioctl_xfern_compat() has no PCM state check, it may go further and hit the sanity check pcm_sanity_check() when the ioctl is called right after open. It may eventually spew a kernel warning, as triggered by syzbot, depending on kconfig.
The lack of PCM state check there was just an oversight. Although it's no real crash, the spurious kernel warning is annoying, so let's add the proper check.
Reported-by: syzbot+1dac3a4f6bc9c1c675d4@syzkaller.appspotmail.com Cc: stable@vger.kernel.org Signed-off-by: Takashi Iwai tiwai@suse.de Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- sound/core/pcm_compat.c | 2 ++ 1 file changed, 2 insertions(+)
--- a/sound/core/pcm_compat.c +++ b/sound/core/pcm_compat.c @@ -426,6 +426,8 @@ static int snd_pcm_ioctl_xfern_compat(st return -ENOTTY; if (substream->stream != dir) return -EINVAL; + if (substream->runtime->status->state == SNDRV_PCM_STATE_OPEN) + return -EBADFD;
if ((ch = substream->runtime->channels) > 128) return -EINVAL;