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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        syzbot+23b22dc2e0b81cbfcc95@syzkaller.appspotmail.com,
        Takashi Iwai <tiwai@suse.de>
Subject: [PATCH 4.9 41/71] ALSA: pcm: oss: Remove superfluous WARN_ON() for mulaw sanity check
Date:   Fri, 11 Sep 2020 14:46:25 +0200
Message-Id: <20200911122506.974371137@linuxfoundation.org>
In-Reply-To: <20200911122504.928931589@linuxfoundation.org>
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From: Takashi Iwai <tiwai@suse.de>

commit 949a1ebe8cea7b342085cb6a4946b498306b9493 upstream.

The PCM OSS mulaw plugin has a check of the format of the counter part
whether it's a linear format.  The check is with snd_BUG_ON() that
emits WARN_ON() when the debug config is set, and it confuses
syzkaller as if it were a serious issue.  Let's drop snd_BUG_ON() for
avoiding that.

While we're at it, correct the error code to a more suitable, EINVAL.

Reported-by: syzbot+23b22dc2e0b81cbfcc95@syzkaller.appspotmail.com
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20200901131802.18157-1-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 sound/core/oss/mulaw.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/sound/core/oss/mulaw.c
+++ b/sound/core/oss/mulaw.c
@@ -329,8 +329,8 @@ int snd_pcm_plugin_build_mulaw(struct sn
 		snd_BUG();
 		return -EINVAL;
 	}
-	if (snd_BUG_ON(!snd_pcm_format_linear(format->format)))
-		return -ENXIO;
+	if (!snd_pcm_format_linear(format->format))
+		return -EINVAL;
 
 	err = snd_pcm_plugin_build(plug, "Mu-Law<->linear conversion",
 				   src_format, dst_format,