diff mbox series

ASoC: mediatek: mt8186: Fix mutex double unlock in GPIO request

Message ID 20220617100632.1447811-1-fshao@chromium.org (mailing list archive)
State New, archived
Headers show
Series ASoC: mediatek: mt8186: Fix mutex double unlock in GPIO request | expand

Commit Message

Fei Shao June 17, 2022, 10:06 a.m. UTC
The lockdep mechanism reveals an unbalanced unlocking on MT8186:

  [    2.993966] WARNING: bad unlock balance detected!
  [    2.993971] 5.15.46-421fef3b44d7-lockdep #16 Not tainted
  [    2.993978] -------------------------------------
  [    2.993983] kworker/u16:1/10 is trying to release lock (gpio_request_mutex) at:
  [    2.993994] [<ffffffdcd9adebf8>] mt8186_afe_gpio_request+0xf8/0x210
  [    2.994012] but there are no more locks to release!
  [    2.994017]
  [    2.994017] other info that might help us debug this:
  [    2.994022] 3 locks held by kworker/u16:1/10:
  [    2.994028]  #0: ffffff80c004a148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x1a8/0x364
  [    2.994054]  #1: ffffffc0080d3d58 (deferred_probe_work){+.+.}-{0:0}, at: process_one_work+0x1d0/0x364
  [    2.994074]  #2: ffffff80c12ab9a0 (&dev->mutex){....}-{3:3}, at: __device_attach+0x44/0x150
  [    2.994096]
  [    2.994096] stack backtrace:
  [    2.994102] CPU: 6 PID: 10 Comm: kworker/u16:1 Not tainted 5.15.46-421fef3b44d7-lockdep #16 a2af0e2c6b3eeab6799b5aa8091c1d05d3a7bbb1
  [    2.994113] Hardware name: Google Kingler board (DT)
  [    2.994120] Workqueue: events_unbound deferred_probe_work_func
  [    2.994130] Call trace:
  [    2.994135]  dump_backtrace+0x0/0x1d4
  [    2.994144]  show_stack+0x20/0x2c
  [    2.994152]  dump_stack_lvl+0x78/0x9c
  [    2.994163]  dump_stack+0x18/0x44
  [    2.994172]  print_unlock_imbalance_bug+0xf0/0xf4
  [    2.994184]  lock_release+0x150/0x388
  [    2.994193]  __mutex_unlock_slowpath+0x4c/0x1bc
  [    2.994202]  mutex_unlock+0x44/0x50
  [    2.994210]  mt8186_afe_gpio_request+0xf8/0x210
  [    2.994220]  mt8186_afe_gpio_init+0xcc/0x134
  [    2.994230]  mt8186_mt6366_rt1019_rt5682s_dev_probe+0x14c/0x220
  [    2.994238]  platform_probe+0xb0/0xd0
  [    2.994247]  really_probe+0xcc/0x2c8
  [    2.994253]  __driver_probe_device+0xbc/0xe8
  [    2.994264]  driver_probe_device+0x48/0xf0
  [    2.994271]  __device_attach_driver+0xa0/0xc8
  [    2.994278]  bus_for_each_drv+0x8c/0xd8
  [    2.994288]  __device_attach+0xc4/0x150
  [    2.994298]  device_initial_probe+0x1c/0x28
  [    2.994308]  bus_probe_device+0x3c/0xa0
  [    2.994318]  deferred_probe_work_func+0xa0/0xe0
  [    2.994325]  process_one_work+0x208/0x364
  [    2.994334]  worker_thread+0x288/0x3fc
  [    2.994343]  kthread+0x140/0x160
  [    2.994351]  ret_from_fork+0x10/0x20

The cause is that the mutex will be double unlocked if dai is unknown
during GPIO selection, and this patch fixes it.

Fixes: cfa9a966f12a ("ASoC: mediatek: mt8186: support gpio control in platform driver")

Signed-off-by: Fei Shao <fshao@chromium.org>
---

 sound/soc/mediatek/mt8186/mt8186-afe-gpio.c | 1 -
 1 file changed, 1 deletion(-)

Comments

Mark Brown June 17, 2022, 10:43 a.m. UTC | #1
On Fri, Jun 17, 2022 at 06:06:33PM +0800, Fei Shao wrote:
> The lockdep mechanism reveals an unbalanced unlocking on MT8186:
> 
>   [    2.993966] WARNING: bad unlock balance detected!
>   [    2.993971] 5.15.46-421fef3b44d7-lockdep #16 Not tainted
>   [    2.993978] -------------------------------------
>   [    2.993983] kworker/u16:1/10 is trying to release lock (gpio_request_mutex) at:
>   [    2.993994] [<ffffffdcd9adebf8>] mt8186_afe_gpio_request+0xf8/0x210
>   [    2.994012] but there are no more locks to release!
>   [    2.994017]
>   [    2.994017] other info that might help us debug this:

Please think hard before including complete backtraces in upstream
reports, they are very large and contain almost no useful information
relative to their size so often obscure the relevant content in your
message. If part of the backtrace is usefully illustrative (it often is
for search engines if nothing else) then it's usually better to pull out
the relevant sections.
Fei Shao June 17, 2022, 11:07 a.m. UTC | #2
On Fri, Jun 17, 2022 at 6:43 PM Mark Brown <broonie@kernel.org> wrote:
>
> On Fri, Jun 17, 2022 at 06:06:33PM +0800, Fei Shao wrote:
> > The lockdep mechanism reveals an unbalanced unlocking on MT8186:
> >
> >   [    2.993966] WARNING: bad unlock balance detected!
> >   [    2.993971] 5.15.46-421fef3b44d7-lockdep #16 Not tainted
> >   [    2.993978] -------------------------------------
> >   [    2.993983] kworker/u16:1/10 is trying to release lock (gpio_request_mutex) at:
> >   [    2.993994] [<ffffffdcd9adebf8>] mt8186_afe_gpio_request+0xf8/0x210
> >   [    2.994012] but there are no more locks to release!
> >   [    2.994017]
> >   [    2.994017] other info that might help us debug this:
>
> Please think hard before including complete backtraces in upstream
> reports, they are very large and contain almost no useful information
> relative to their size so often obscure the relevant content in your
> message. If part of the backtrace is usefully illustrative (it often is
> for search engines if nothing else) then it's usually better to pull out
> the relevant sections.

Agreed, I'll resend the patch. Thank you for the feedback.

Regards,
Fei
Mark Brown June 17, 2022, 11:19 p.m. UTC | #3
On Fri, 17 Jun 2022 18:06:33 +0800, Fei Shao wrote:
> The lockdep mechanism reveals an unbalanced unlocking on MT8186:
> 
>   [    2.993966] WARNING: bad unlock balance detected!
>   [    2.993971] 5.15.46-421fef3b44d7-lockdep #16 Not tainted
>   [    2.993978] -------------------------------------
>   [    2.993983] kworker/u16:1/10 is trying to release lock (gpio_request_mutex) at:
>   [    2.993994] [<ffffffdcd9adebf8>] mt8186_afe_gpio_request+0xf8/0x210
>   [    2.994012] but there are no more locks to release!
>   [    2.994017]
>   [    2.994017] other info that might help us debug this:
>   [    2.994022] 3 locks held by kworker/u16:1/10:
>   [    2.994028]  #0: ffffff80c004a148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x1a8/0x364
>   [    2.994054]  #1: ffffffc0080d3d58 (deferred_probe_work){+.+.}-{0:0}, at: process_one_work+0x1d0/0x364
>   [    2.994074]  #2: ffffff80c12ab9a0 (&dev->mutex){....}-{3:3}, at: __device_attach+0x44/0x150
>   [    2.994096]
>   [    2.994096] stack backtrace:
>   [    2.994102] CPU: 6 PID: 10 Comm: kworker/u16:1 Not tainted 5.15.46-421fef3b44d7-lockdep #16 a2af0e2c6b3eeab6799b5aa8091c1d05d3a7bbb1
>   [    2.994113] Hardware name: Google Kingler board (DT)
>   [    2.994120] Workqueue: events_unbound deferred_probe_work_func
>   [    2.994130] Call trace:
>   [    2.994135]  dump_backtrace+0x0/0x1d4
>   [    2.994144]  show_stack+0x20/0x2c
>   [    2.994152]  dump_stack_lvl+0x78/0x9c
>   [    2.994163]  dump_stack+0x18/0x44
>   [    2.994172]  print_unlock_imbalance_bug+0xf0/0xf4
>   [    2.994184]  lock_release+0x150/0x388
>   [    2.994193]  __mutex_unlock_slowpath+0x4c/0x1bc
>   [    2.994202]  mutex_unlock+0x44/0x50
>   [    2.994210]  mt8186_afe_gpio_request+0xf8/0x210
>   [    2.994220]  mt8186_afe_gpio_init+0xcc/0x134
>   [    2.994230]  mt8186_mt6366_rt1019_rt5682s_dev_probe+0x14c/0x220
>   [    2.994238]  platform_probe+0xb0/0xd0
>   [    2.994247]  really_probe+0xcc/0x2c8
>   [    2.994253]  __driver_probe_device+0xbc/0xe8
>   [    2.994264]  driver_probe_device+0x48/0xf0
>   [    2.994271]  __device_attach_driver+0xa0/0xc8
>   [    2.994278]  bus_for_each_drv+0x8c/0xd8
>   [    2.994288]  __device_attach+0xc4/0x150
>   [    2.994298]  device_initial_probe+0x1c/0x28
>   [    2.994308]  bus_probe_device+0x3c/0xa0
>   [    2.994318]  deferred_probe_work_func+0xa0/0xe0
>   [    2.994325]  process_one_work+0x208/0x364
>   [    2.994334]  worker_thread+0x288/0x3fc
>   [    2.994343]  kthread+0x140/0x160
>   [    2.994351]  ret_from_fork+0x10/0x20
> 
> [...]

Applied to

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound.git for-next

Thanks!

[1/1] ASoC: mediatek: mt8186: Fix mutex double unlock in GPIO request
      commit: 6c9e9046e1ff356bda66661213735d33c6cfea53

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
diff mbox series

Patch

diff --git a/sound/soc/mediatek/mt8186/mt8186-afe-gpio.c b/sound/soc/mediatek/mt8186/mt8186-afe-gpio.c
index 255ffba637d3..274c0c8ec2f2 100644
--- a/sound/soc/mediatek/mt8186/mt8186-afe-gpio.c
+++ b/sound/soc/mediatek/mt8186/mt8186-afe-gpio.c
@@ -230,7 +230,6 @@  int mt8186_afe_gpio_request(struct device *dev, bool enable,
 		sel = enable ? MT8186_AFE_GPIO_PCM_ON : MT8186_AFE_GPIO_PCM_OFF;
 		break;
 	default:
-		mutex_unlock(&gpio_request_mutex);
 		dev_err(dev, "%s(), invalid dai %d\n", __func__, dai);
 		goto unlock;
 	}