This is a note to let you know that I've just added the patch titled
ALSA: aloop: Release cable upon open error path
to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
alsa-aloop-release-cable-upon-open-error-path.patch
and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 9685347aa0a5c2869058ca6ab79fd8e93084a67f Mon Sep 17 00:00:00 2001
From: Takashi Iwai <tiwai@xxxxxxx>
Date: Fri, 5 Jan 2018 16:09:47 +0100
Subject: ALSA: aloop: Release cable upon open error path
From: Takashi Iwai <tiwai@xxxxxxx>
commit 9685347aa0a5c2869058ca6ab79fd8e93084a67f upstream.
The aloop runtime object and its assignment in the cable are left even
when opening a substream fails. This doesn't mean any memory leak,
but it still keeps the invalid pointer that may be referred by the
another side of the cable spontaneously, which is a potential Oops
cause.
Clean up the cable assignment and the empty cable upon the error path
properly.
Fixes: 597603d615d2 ("ALSA: introduce the snd-aloop module for the PCM loopback")
Signed-off-by: Takashi Iwai <tiwai@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
sound/drivers/aloop.c | 38 +++++++++++++++++++++++++-------------
1 file changed, 25 insertions(+), 13 deletions(-)
--- a/sound/drivers/aloop.c
+++ b/sound/drivers/aloop.c
@@ -658,12 +658,31 @@ static int rule_channels(struct snd_pcm_
return snd_interval_refine(hw_param_interval(params, rule->var), &t);
}
+static void free_cable(struct snd_pcm_substream *substream)
+{
+ struct loopback *loopback = substream->private_data;
+ int dev = get_cable_index(substream);
+ struct loopback_cable *cable;
+
+ cable = loopback->cables[substream->number][dev];
+ if (!cable)
+ return;
+ if (cable->streams[!substream->stream]) {
+ /* other stream is still alive */
+ cable->streams[substream->stream] = NULL;
+ } else {
+ /* free the cable */
+ loopback->cables[substream->number][dev] = NULL;
+ kfree(cable);
+ }
+}
+
static int loopback_open(struct snd_pcm_substream *substream)
{
struct snd_pcm_runtime *runtime = substream->runtime;
struct loopback *loopback = substream->private_data;
struct loopback_pcm *dpcm;
- struct loopback_cable *cable;
+ struct loopback_cable *cable = NULL;
int err = 0;
int dev = get_cable_index(substream);
@@ -682,7 +701,6 @@ static int loopback_open(struct snd_pcm_
if (!cable) {
cable = kzalloc(sizeof(*cable), GFP_KERNEL);
if (!cable) {
- kfree(dpcm);
err = -ENOMEM;
goto unlock;
}
@@ -724,6 +742,10 @@ static int loopback_open(struct snd_pcm_
else
runtime->hw = cable->hw;
unlock:
+ if (err < 0) {
+ free_cable(substream);
+ kfree(dpcm);
+ }
mutex_unlock(&loopback->cable_lock);
return err;
}
@@ -732,20 +754,10 @@ static int loopback_close(struct snd_pcm
{
struct loopback *loopback = substream->private_data;
struct loopback_pcm *dpcm = substream->runtime->private_data;
- struct loopback_cable *cable;
- int dev = get_cable_index(substream);
loopback_timer_stop(dpcm);
mutex_lock(&loopback->cable_lock);
- cable = loopback->cables[substream->number][dev];
- if (cable->streams[!substream->stream]) {
- /* other stream is still alive */
- cable->streams[substream->stream] = NULL;
- } else {
- /* free the cable */
- loopback->cables[substream->number][dev] = NULL;
- kfree(cable);
- }
+ free_cable(substream);
mutex_unlock(&loopback->cable_lock);
return 0;
}
Patches currently in stable-queue which might be from tiwai@xxxxxxx are
queue-4.4/alsa-pcm-remove-incorrect-snd_bug_on-usages.patch
queue-4.4/alsa-aloop-fix-inconsistent-format-due-to-incomplete-rule.patch
queue-4.4/alsa-pcm-add-missing-error-checks-in-oss-emulation-plugin-builder.patch
queue-4.4/alsa-pcm-abort-properly-at-pending-signal-in-oss-read-write-loops.patch
queue-4.4/alsa-pcm-allow-aborting-mutex-lock-at-oss-read-write-loops.patch
queue-4.4/alsa-aloop-fix-racy-hw-constraints-adjustment.patch
queue-4.4/alsa-aloop-release-cable-upon-open-error-path.patch