[PATCH] staging: bcm2835-audio: Disconnect and free vchi_instance on module_exit()

Kirill Marinushkin
2018-04-17T05:00:28Z

In the current implementation, vchi_instance is inited during the first
call of bcm2835_audio_open_connection(), and is never freed. It causes a
memory leak when the module `snd_bcm2835` is removed.

Here is how this commit fixes it:

* the VCHI context (including vchi_instance) is created once in the
platform's devres
* the VCHI context is allocated and connected once during module_init()
* all created bcm2835_chips have a pointer to this VCHI context
* bcm2835_audio_open_connection() can access the VCHI context through the
associated bcm2835_chip
* the VCHI context is disconnected and freed once during module_exit()

After this commit is applied, I don't see other issues with the module's
init/exit, so I also remove the associated TODO task.

Steps to reproduce the memory leak before this commit:

~~~~
root@raspberrypi:/home/pi# aplay test0.wav
Playing WAVE 'test0.wav' : Signed 16 bit Little Endian, Rate 44100 Hz, Ster
^CAborted by signal Interrupt...
root@raspberrypi:/home/pi# rmmod snd_bcm2835
root@raspberrypi:/home/pi# modprobe snd_bcm2835
root@raspberrypi:/home/pi# aplay test0.wav
Playing WAVE 'test0.wav' : Signed 16 bit Little Endian, Rate 44100 Hz, Ster
^CAborted by signal Interrupt...
root@raspberrypi:/home/pi# echo scan > /sys/kernel/debug/kmemleak
root@raspberrypi:/home/pi# cat /sys/kernel/debug/kmemleak
unreferenced object 0xb6794c00 (size 128):
comm "aplay", pid 406, jiffies 36870 (age 116.650s)
hex dump (first 32 bytes):
08 a5 82 81 01 00 00 00 08 4c 79 b6 08 4c 79 b6 .........Ly..Ly.
00 00 00 00 00 00 00 00 ad 4e ad de ff ff ff ff .........N......
backtrace:
[<802af5e0>] kmem_cache_alloc_trace+0x294/0x3d0
[<806ce620>] vchiq_initialise+0x98/0x1b0
[<806d0b34>] vchi_initialise+0x24/0x34
[<7f1311ec>] 0x7f1311ec
[<7f1303bc>] 0x7f1303bc
[<7f130590>] 0x7f130590
[<7f111fd8>] snd_pcm_open_substream+0x68/0xc4 [snd_pcm]
[<7f112108>] snd_pcm_open+0xd4/0x248 [snd_pcm]
[<7f112334>] snd_pcm_playback_open+0x4c/0x6c [snd_pcm]
[<7f0e250c>] snd_open+0xa8/0x14c [snd]
[<802ce590>] chrdev_open+0xac/0x188
[<802c57b4>] do_dentry_open+0x10c/0x314
[<802c6ba8>] vfs_open+0x5c/0x88
[<802d9a68>] path_openat+0x368/0x944
[<802dacd4>] do_filp_open+0x70/0xc4
[<802c6f70>] do_sys_open+0x110/0x1d4
~~~~

Signed-off-by: Kirill Marinushkin <k.marinushkin@gmail.com>
Cc: Eric Anholt <eric@anholt.net>
Cc: Stefan Wahren <stefan.wahren@i2se.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: Ray Jui <rjui@broadcom.com>
Cc: Scott Branden <sbranden@broadcom.com>
Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: bcm-kernel-feedback-list@broadcom.com
Cc: linux-rpi-kernel@lists.infradead.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: devel@driverdev.osuosl.org
Cc: linux-kernel@vger.kernel.org
---
.../vc04_services/bcm2835-audio/bcm2835-vchiq.c | 64 +++++++++++++---------
.../staging/vc04_services/bcm2835-audio/bcm2835.c | 43 ++++++++++++++-
.../staging/vc04_services/bcm2835-audio/bcm2835.h | 12 ++++
3 files changed, 91 insertions(+), 28 deletions(-)

diff --git a/drivers/staging/vc04_services/bcm2835-audio/bcm2835-vchiq.c b/drivers/staging/vc04_services/bcm2835-audio/bcm2835-vchiq.c
index 3c6f1d91d22d..389a18f9350a 100644
--- a/drivers/staging/vc04_services/bcm2835-audio/bcm2835-vchiq.c
+++ b/drivers/staging/vc04_services/bcm2835-audio/bcm2835-vchiq.c
@@ -33,7 +33,6 @@

/* ---- Include Files -------------------------------------------------------- */

-#include "interface/vchi/vchi.h"
#include "vc_vchi_audioserv_defs.h"

/* ---- Private Constants and Types ------------------------------------------ */
@@ -371,14 +370,46 @@ static int vc_vchi_audio_deinit(struct bcm2835_audio_instance *instance)
return 0;
}

+int bcm2835_new_vchi_ctx(struct bcm2835_vchi_ctx *vchi_ctx)
+{
+ int ret;
+
+ /* Initialize and create a VCHI connection */
+ ret = vchi_initialise(&vchi_ctx->vchi_instance);
+ if (ret) {
+ LOG_ERR("%s: failed to initialise VCHI instance (ret=%d)\n",
+ __func__, ret);
+
+ return -EIO;
+ }
+
+ ret = vchi_connect(NULL, 0, vchi_ctx->vchi_instance);
+ if (ret) {
+ LOG_ERR("%s: failed to connect VCHI instance (ret=%d)\n",
+ __func__, ret);
+
+ kfree(vchi_ctx->vchi_instance);
+ vchi_ctx->vchi_instance = NULL;
+
+ return -EIO;
+ }
+
+ return 0;
+}
+
+void bcm2835_free_vchi_ctx(struct bcm2835_vchi_ctx *vchi_ctx)
+{
+ /* Close the VCHI connection - it will also free vchi_instance */
+ WARN_ON(vchi_disconnect(vchi_ctx->vchi_instance));
+
+ vchi_ctx->vchi_instance = NULL;
+}
+
static int bcm2835_audio_open_connection(struct bcm2835_alsa_stream *alsa_stream)
{
- static VCHI_INSTANCE_T vchi_instance;
- static VCHI_CONNECTION_T *vchi_connection;
- static int initted;
struct bcm2835_audio_instance *instance =
(struct bcm2835_audio_instance *)alsa_stream->instance;
- int ret;
+ struct bcm2835_vchi_ctx *vhci_ctx = alsa_stream->chip->vchi_ctx;

LOG_INFO("%s: start\n", __func__);
BUG_ON(instance);
@@ -390,28 +421,9 @@ static int bcm2835_audio_open_connection(struct bcm2835_alsa_stream *alsa_stream
return 0;
}

- /* Initialize and create a VCHI connection */
- if (!initted) {
- ret = vchi_initialise(&vchi_instance);
- if (ret) {
- LOG_ERR("%s: failed to initialise VCHI instance (ret=%d)\n",
- __func__, ret);
-
- return -EIO;
- }
- ret = vchi_connect(NULL, 0, vchi_instance);
- if (ret) {
- LOG_ERR("%s: failed to connect VCHI instance (ret=%d)\n",
- __func__, ret);
-
- kfree(vchi_instance);
- return -EIO;
- }
- initted = 1;
- }
-
/* Initialize an instance of the audio service */
- instance = vc_vchi_audio_init(vchi_instance, &vchi_connection, 1);
+ instance = vc_vchi_audio_init(vhci_ctx->vchi_instance,
+ &vhci_ctx->vchi_connection, 1);

if (IS_ERR(instance)) {
LOG_ERR("%s: failed to initialize audio service\n", __func__);
diff --git a/drivers/staging/vc04_services/bcm2835-audio/bcm2835.c b/drivers/staging/vc04_services/bcm2835-audio/bcm2835.c
index 9030d71a3d0b..009c972d93d6 100644
--- a/drivers/staging/vc04_services/bcm2835-audio/bcm2835.c
+++ b/drivers/staging/vc04_services/bcm2835-audio/bcm2835.c
@@ -65,6 +65,36 @@ static int snd_devm_add_child(struct device *dev, struct device *child)
return 0;
}

+static void bcm2835_devm_free_vchi_ctx(struct device *dev, void *res)
+{
+ struct bcm2835_vchi_ctx *vchi_ctx = res;
+
+ bcm2835_free_vchi_ctx(vchi_ctx);
+}
+
+static int bcm2835_devm_add_vchi_ctx(struct device *dev)
+{
+ struct bcm2835_vchi_ctx *vchi_ctx;
+ int ret;
+
+ vchi_ctx = devres_alloc(bcm2835_devm_free_vchi_ctx, sizeof(*vchi_ctx),
+ GFP_KERNEL);
+ if (!vchi_ctx)
+ return -ENOMEM;
+
+ memset(vchi_ctx, 0, sizeof(*vchi_ctx));
+
+ ret = bcm2835_new_vchi_ctx(vchi_ctx);
+ if (ret) {
+ devres_free(vchi_ctx);
+ return ret;
+ }
+
+ devres_add(dev, vchi_ctx);
+
+ return 0;
+}
+
static void snd_bcm2835_release(struct device *dev)
{
struct bcm2835_chip *chip = dev_get_drvdata(dev);
@@ -106,8 +136,6 @@ static int snd_bcm2835_dev_free(struct snd_device *device)
struct bcm2835_chip *chip = device->device_data;
struct snd_card *card = chip->card;

- /* TODO: free pcm, ctl */
-
snd_device_free(card, chip);

return 0;
@@ -133,6 +161,13 @@ static int snd_bcm2835_create(struct snd_card *card,

chip->card = card;

+ chip->vchi_ctx = devres_find(card->dev->parent,
+ bcm2835_devm_free_vchi_ctx, NULL, NULL);
+ if (!chip->vchi_ctx) {
+ kfree(chip);
+ return err;
+ }
+
err = snd_device_new(card, SNDRV_DEV_LOWLEVEL, chip, &ops);
if (err) {
kfree(chip);
@@ -403,6 +438,10 @@ static int snd_bcm2835_alsa_probe_dt(struct platform_device *pdev)
numchans);
}

+ err = bcm2835_devm_add_vchi_ctx(dev);
+ if (err)
+ return err;
+
err = snd_add_child_devices(dev, numchans);
if (err)
return err;
diff --git a/drivers/staging/vc04_services/bcm2835-audio/bcm2835.h b/drivers/staging/vc04_services/bcm2835-audio/bcm2835.h
index f1e43e45fd67..1c82c2ee47dc 100644
--- a/drivers/staging/vc04_services/bcm2835-audio/bcm2835.h
+++ b/drivers/staging/vc04_services/bcm2835-audio/bcm2835.h
@@ -26,6 +26,8 @@
#include <sound/pcm-indirect.h>
#include <linux/workqueue.h>

+#include "interface/vchi/vchi.h"
+
/*
* #define AUDIO_DEBUG_ENABLE
* #define AUDIO_VERBOSE_DEBUG_ENABLE
@@ -97,6 +99,11 @@ enum snd_bcm2835_ctrl {
PCM_PLAYBACK_DEVICE,
};

+struct bcm2835_vchi_ctx {
+ VCHI_INSTANCE_T vchi_instance;
+ VCHI_CONNECTION_T *vchi_connection;
+};
+
/* definition of the chip-specific record */
struct bcm2835_chip {
struct snd_card *card;
@@ -115,6 +122,8 @@ struct bcm2835_chip {
unsigned int opened;
unsigned int spdif_status;
struct mutex audio_mutex;
+
+ struct bcm2835_vchi_ctx *vchi_ctx;
};

struct bcm2835_alsa_stream {
@@ -153,6 +162,9 @@ int snd_bcm2835_new_simple_pcm(struct bcm2835_chip *chip,
int snd_bcm2835_new_hdmi_ctl(struct bcm2835_chip *chip);
int snd_bcm2835_new_headphones_ctl(struct bcm2835_chip *chip);

+int bcm2835_new_vchi_ctx(struct bcm2835_vchi_ctx *vchi_ctx);
+void bcm2835_free_vchi_ctx(struct bcm2835_vchi_ctx *vchi_ctx);
+
int bcm2835_audio_open(struct bcm2835_alsa_stream *alsa_stream);
int bcm2835_audio_close(struct bcm2835_alsa_stream *alsa_stream);
int bcm2835_audio_set_params(struct bcm2835_alsa_stream *alsa_stream,
--
2.13.6

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