The patch ASoC: max98090: fix lockdep warning has been applied to the asoc tree at https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound.git for-5.6 All being well this means that it will be integrated into the linux-next tree (usually sometime in the next 24 hours) and sent to Linus during the next merge window (or sooner if it is a bug fix), however if problems are discovered then the patch may be dropped or reverted. You may get further e-mails resulting from automated or manual testing and review of the tree, please engage with people reporting problems and send followup patches addressing any issues that are reported if needed. If any updates are required or you are submitting further changes they should be sent as incremental updates against current git, existing patches will not be replaced. Please add any relevant lists and maintainers to the CCs when replying to this mail. Thanks, Mark >From 2dc98af62c32ff6c8b9a32365346c5c407e291a8 Mon Sep 17 00:00:00 2001 From: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx> Date: Wed, 8 Jan 2020 12:50:07 +0100 Subject: [PATCH] ASoC: max98090: fix lockdep warning Commit 62d5ae4cafb7 ("ASoC: max98090: save and restore SHDN when changing sensitive registers") extended the code for handling many controls by adding a custom put function to them. That new custom put function properly handles relations between codec's hardware registers. However they used card->dapm_mutex to properly serialize those operations. This in turn triggers a lockdep warning about possible circular dependency. Fix this by introducing a separate mutex only for serializing the SHDN hardware register related operations. This fixes the following lockdep warning observed on Exynos4412-based Odroid U3 board: ====================================================== WARNING: possible circular locking dependency detected 5.5.0-rc5-next-20200107 #166 Not tainted ------------------------------------------------------ alsactl/1104 is trying to acquire lock: ed0d50f4 (&card->dapm_mutex){+.+.}, at: max98090_shdn_save+0x1c/0x28 but task is already holding lock: edb4b49c (&card->controls_rwsem){++++}, at: snd_ctl_ioctl+0xcc/0xbb8 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&card->controls_rwsem){++++}: snd_ctl_add_replace+0x3c/0x84 dapm_create_or_share_kcontrol+0x24c/0x2e0 snd_soc_dapm_new_widgets+0x308/0x594 snd_soc_bind_card+0x80c/0xad4 devm_snd_soc_register_card+0x34/0x6c odroid_audio_probe+0x288/0x34c platform_drv_probe+0x6c/0xa4 really_probe+0x200/0x490 driver_probe_device+0x78/0x1f8 bus_for_each_drv+0x74/0xb8 __device_attach+0xd4/0x16c bus_probe_device+0x88/0x90 deferred_probe_work_func+0x3c/0xd0 process_one_work+0x22c/0x7c4 worker_thread+0x44/0x524 kthread+0x130/0x164 ret_from_fork+0x14/0x20 0x0 -> #0 (&card->dapm_mutex){+.+.}: lock_acquire+0xe8/0x270 __mutex_lock+0x9c/0xb18 mutex_lock_nested+0x1c/0x24 max98090_shdn_save+0x1c/0x28 max98090_put_enum_double+0x20/0x40 snd_ctl_ioctl+0x190/0xbb8 ksys_ioctl+0x470/0xaf8 ret_fast_syscall+0x0/0x28 0xbefaa564 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&card->controls_rwsem); lock(&card->dapm_mutex); lock(&card->controls_rwsem); lock(&card->dapm_mutex); *** DEADLOCK *** 1 lock held by alsactl/1104: #0: edb4b49c (&card->controls_rwsem){++++}, at: snd_ctl_ioctl+0xcc/0xbb8 stack backtrace: CPU: 0 PID: 1104 Comm: alsactl Not tainted 5.5.0-rc5-next-20200107 #166 Hardware name: SAMSUNG EXYNOS (Flattened Device Tree) (unwind_backtrace) from [<c010e180>] (show_stack+0x10/0x14) (show_stack) from [<c0b2a09c>] (dump_stack+0xb4/0xe0) (dump_stack) from [<c018a1c0>] (check_noncircular+0x1ec/0x208) (check_noncircular) from [<c018c5dc>] (__lock_acquire+0x1210/0x25ec) (__lock_acquire) from [<c018e2d8>] (lock_acquire+0xe8/0x270) (lock_acquire) from [<c0b49678>] (__mutex_lock+0x9c/0xb18) (__mutex_lock) from [<c0b4a110>] (mutex_lock_nested+0x1c/0x24) (mutex_lock_nested) from [<c0839b3c>] (max98090_shdn_save+0x1c/0x28) (max98090_shdn_save) from [<c083a5b8>] (max98090_put_enum_double+0x20/0x40) (max98090_put_enum_double) from [<c080d0e8>] (snd_ctl_ioctl+0x190/0xbb8) (snd_ctl_ioctl) from [<c02cafec>] (ksys_ioctl+0x470/0xaf8) (ksys_ioctl) from [<c0101000>] (ret_fast_syscall+0x0/0x28) ... Fixes: 62d5ae4cafb7 ("ASoC: max98090: save and restore SHDN when changing sensitive registers") Signed-off-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx> Link: https://lore.kernel.org/r/20200108115007.31095-2-m.szyprowski@xxxxxxxxxxx Signed-off-by: Mark Brown <broonie@xxxxxxxxxx> --- sound/soc/codecs/max98090.c | 10 ++++++---- sound/soc/codecs/max98090.h | 1 + 2 files changed, 7 insertions(+), 4 deletions(-) diff --git a/sound/soc/codecs/max98090.c b/sound/soc/codecs/max98090.c index ede03663cbed..ba0e3ba162f8 100644 --- a/sound/soc/codecs/max98090.c +++ b/sound/soc/codecs/max98090.c @@ -52,14 +52,14 @@ static void max98090_shdn_restore_locked(struct max98090_priv *max98090) static void max98090_shdn_save(struct max98090_priv *max98090) { - mutex_lock(&max98090->component->card->dapm_mutex); + mutex_lock(&max98090->shdn_lock); max98090_shdn_save_locked(max98090); } static void max98090_shdn_restore(struct max98090_priv *max98090) { max98090_shdn_restore_locked(max98090); - mutex_unlock(&max98090->component->card->dapm_mutex); + mutex_unlock(&max98090->shdn_lock); } static int max98090_put_volsw(struct snd_kcontrol *kcontrol, @@ -2313,12 +2313,12 @@ static void max98090_pll_work(struct max98090_priv *max98090) */ /* Toggle shutdown OFF then ON */ - mutex_lock(&component->card->dapm_mutex); + mutex_lock(&max98090->shdn_lock); snd_soc_component_update_bits(component, M98090_REG_DEVICE_SHUTDOWN, M98090_SHDNN_MASK, 0); snd_soc_component_update_bits(component, M98090_REG_DEVICE_SHUTDOWN, M98090_SHDNN_MASK, M98090_SHDNN_MASK); - mutex_unlock(&component->card->dapm_mutex); + mutex_unlock(&max98090->shdn_lock); for (i = 0; i < 10; ++i) { /* Give PLL time to lock */ @@ -2731,6 +2731,8 @@ static int max98090_i2c_probe(struct i2c_client *i2c, if (max98090 == NULL) return -ENOMEM; + mutex_init(&max98090->shdn_lock); + if (ACPI_HANDLE(&i2c->dev)) { acpi_id = acpi_match_device(i2c->dev.driver->acpi_match_table, &i2c->dev); diff --git a/sound/soc/codecs/max98090.h b/sound/soc/codecs/max98090.h index 0a31708b7df7..dabd8be34a01 100644 --- a/sound/soc/codecs/max98090.h +++ b/sound/soc/codecs/max98090.h @@ -1539,6 +1539,7 @@ struct max98090_priv { unsigned int pa2en; unsigned int sidetone; bool master; + struct mutex shdn_lock; int saved_count; int saved_shdn; }; -- 2.20.1
