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From:   Ben Hutchings <ben@decadent.org.uk>
To:     linux-kernel@vger.kernel.org, stable@vger.kernel.org
CC:     akpm@linux-foundation.org, "Takashi Iwai" <tiwai@suse.de>
Date:   Wed, 28 Feb 2018 15:20:18 +0000
Message-ID: <lsq.1519831218.258198970@decadent.org.uk>
Subject: [PATCH 3.16 163/254] ALSA: pcm: Add missing error checks in OSS
 emulation plugin builder
In-Reply-To: <lsq.1519831217.271785318@decadent.org.uk>
Sender: linux-kernel-owner@vger.kernel.org
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3.16.55-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Takashi Iwai <tiwai@suse.de>

commit 6708913750344a900f2e73bfe4a4d6dbbce4fe8d upstream.

In the OSS emulation plugin builder where the frame size is parsed in
the plugin chain, some places miss the possible errors returned from
the plugin src_ or dst_frames callback.

This patch papers over such places.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
 sound/core/oss/pcm_plugin.c | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

--- a/sound/core/oss/pcm_plugin.c
+++ b/sound/core/oss/pcm_plugin.c
@@ -591,18 +591,26 @@ snd_pcm_sframes_t snd_pcm_plug_write_tra
 	snd_pcm_sframes_t frames = size;
 
 	plugin = snd_pcm_plug_first(plug);
-	while (plugin && frames > 0) {
+	while (plugin) {
+		if (frames <= 0)
+			return frames;
 		if ((next = plugin->next) != NULL) {
 			snd_pcm_sframes_t frames1 = frames;
-			if (plugin->dst_frames)
+			if (plugin->dst_frames) {
 				frames1 = plugin->dst_frames(plugin, frames);
+				if (frames1 <= 0)
+					return frames1;
+			}
 			if ((err = next->client_channels(next, frames1, &dst_channels)) < 0) {
 				return err;
 			}
 			if (err != frames1) {
 				frames = err;
-				if (plugin->src_frames)
+				if (plugin->src_frames) {
 					frames = plugin->src_frames(plugin, frames1);
+					if (frames <= 0)
+						return frames;
+				}
 			}
 		} else
 			dst_channels = NULL;