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Message-ID: <9e4fc4a0-370b-9101-2809-4040de58553c@gmail.com>
Date: Tue, 24 Apr 2018 20:27:06 +0200
From: Kirill Marinushkin <k.marinushkin@...il.com>
To: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Andy Shevchenko <andy.shevchenko@...il.com>,
Eric Anholt <eric@...olt.net>,
Stefan Wahren <stefan.wahren@...e.com>,
Florian Fainelli <f.fainelli@...il.com>,
Ray Jui <rjui@...adcom.com>,
Scott Branden <sbranden@...adcom.com>,
Dan Carpenter <dan.carpenter@...cle.com>
Cc: bcm-kernel-feedback-list@...adcom.com,
linux-rpi-kernel@...ts.infradead.org,
linux-arm-kernel@...ts.infradead.org, devel@...verdev.osuosl.org,
linux-kernel@...r.kernel.org
Subject: Re: [RESEND PATCH] staging: bcm2835-audio: Disconnect and free
vchi_instance on module_exit()
@Greg
> I have no idea as the patch is long gone from my queue now. If you
> think all is fine, please resend it and I will be glad to review it
> again.
Stefan, Dan and Andy explained me, what caused the compiler warning in my patch,
and why I couldn't reproduce it. I will fix the root cause, and send the patch v2.
@Stefan
> this is an old toolchain. You can download newer ones here (even for i686):
>
https://releases.linaro.org/components/toolchain/binaries/7.2-2017.11/arm-linux-gnueabihf/
Thank you for the hint. Looks like I will be able to catch this compiler warning
with the newer toolchain.
@Dan
> kbuild is complaining that "err" is uninitialized here but for some
> reason the line numbers are off. It's a real bug.
Thank you for the review. Yes, indeed, this is not correct. I will fix it.
@Andy
> AFAIR I gave you a tag and you again missed it.
> Before sending anything just check twice if all prerequisites are fulfilled.
I think you mix it up. This is a new patch, you didn't review it before.
> And yes, kbuild bot is right. You need to return known value.
Yes, that's right. I will fix it.
Best Regards,
Kirill
On 04/24/18 09:44, Kirill Marinushkin wrote:
> 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@...pberrypi:/home/pi# aplay test0.wav
> Playing WAVE 'test0.wav' : Signed 16 bit Little Endian, Rate 44100 Hz, Ster
> ^CAborted by signal Interrupt...
> root@...pberrypi:/home/pi# rmmod snd_bcm2835
> root@...pberrypi:/home/pi# modprobe snd_bcm2835
> root@...pberrypi:/home/pi# aplay test0.wav
> Playing WAVE 'test0.wav' : Signed 16 bit Little Endian, Rate 44100 Hz, Ster
> ^CAborted by signal Interrupt...
> root@...pberrypi:/home/pi# echo scan > /sys/kernel/debug/kmemleak
> root@...pberrypi:/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@...il.com>
> Cc: Eric Anholt <eric@...olt.net>
> Cc: Stefan Wahren <stefan.wahren@...e.com>
> Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
> Cc: Florian Fainelli <f.fainelli@...il.com>
> Cc: Ray Jui <rjui@...adcom.com>
> Cc: Scott Branden <sbranden@...adcom.com>
> Cc: Andy Shevchenko <andy.shevchenko@...il.com>
> Cc: bcm-kernel-feedback-list@...adcom.com
> Cc: linux-rpi-kernel@...ts.infradead.org
> Cc: linux-arm-kernel@...ts.infradead.org
> Cc: devel@...verdev.osuosl.org
> Cc: linux-kernel@...r.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,
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