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    Subject[PATCH v3] staging: bcm2835-audio: Disconnect and free vchi_instance on module_exit()
    Date
    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: Dan Carpenter <dan.carpenter@oracle.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
    ---
    Chagelog

    v1: Initial patch

    v2: Fixed the compiler warning
    @drivers/staging/vc04_services/bcm2835-audio/bcm2835.c:168
    if (!chip->vchi_ctx) {
    kfree(chip);
    - return err;
    + return -ENODEV;
    }

    v3: Appended this changelog

    .../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..662e05bd8f05 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 -ENODEV;
    + }
    +
    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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      Last update: 2018-04-26 19:34    [W:5.821 / U:0.008 seconds]
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