Commit c0feea594e05 ("workqueue: don't skip lockdep work dependency in
cancel_work_sync()") revealed the following locking issue in the wm8994
codec:
======================================================
WARNING: possible circular locking dependency detected
6.0.0-rc1-00001-gc0feea594e05-dirty #13097 Not tainted
------------------------------------------------------
kworker/1:1/32 is trying to acquire lock:
c2bd4300 (&wm8994->accdet_lock){+.+.}-{3:3}, at: wm1811_mic_work+0x38/0xdc
but task is already holding lock:
f08f5f28 ((work_completion)(&(&wm8994->mic_work)->work)){+.+.}-{0:0}, at: process_one_work+0x1e4/0x778
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #1 ((work_completion)(&(&wm8994->mic_work)->work)){+.+.}-{0:0}:
__cancel_work_timer+0x198/0x22c
wm1811_jackdet_irq+0x124/0x238
process_one_work+0x288/0x778
worker_thread+0x44/0x504
kthread+0xf0/0x124
ret_from_fork+0x14/0x2c
0x0
-> #0 (&wm8994->accdet_lock){+.+.}-{3:3}:
lock_acquire+0x124/0x3e4
__mutex_lock+0x90/0x948
mutex_lock_nested+0x1c/0x24
wm1811_mic_work+0x38/0xdc
process_one_work+0x288/0x778
worker_thread+0x44/0x504
kthread+0xf0/0x124
ret_from_fork+0x14/0x2c
0x0
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock((work_completion)(&(&wm8994->mic_work)->work));
lock(&wm8994->accdet_lock);
lock((work_completion)(&(&wm8994->mic_work)->work));
lock(&wm8994->accdet_lock);
*** DEADLOCK ***
2 locks held by kworker/1:1/32:
#0: c1c072a8 ((wq_completion)events_power_efficient){+.+.}-{0:0}, at: process_one_work+0x1e4/0x778
#1: f08f5f28 ((work_completion)(&(&wm8994->mic_work)->work)){+.+.}-{0:0}, at: process_one_work+0x1e4/0x778
stack backtrace:
CPU: 1 PID: 32 Comm: kworker/1:1 Not tainted 6.0.0-rc1-00001-gc0feea594e05-dirty #13097
Hardware name: Samsung Exynos (Flattened Device Tree)
Workqueue: events_power_efficient wm1811_mic_work
unwind_backtrace from show_stack+0x10/0x14
show_stack from dump_stack_lvl+0x58/0x70
dump_stack_lvl from check_noncircular+0xf0/0x158
check_noncircular from __lock_acquire+0x15e8/0x2a7c
__lock_acquire from lock_acquire+0x124/0x3e4
lock_acquire from __mutex_lock+0x90/0x948
__mutex_lock from mutex_lock_nested+0x1c/0x24
mutex_lock_nested from wm1811_mic_work+0x38/0xdc
wm1811_mic_work from process_one_work+0x288/0x778
process_one_work from worker_thread+0x44/0x504
worker_thread from kthread+0xf0/0x124
kthread from ret_from_fork+0x14/0x2c
Exception stack(0xf08f5fb0 to 0xf08f5ff8)
...
--->8---
Fix this by dropping wm8994->accdet_lock while calling
cancel_delayed_work_sync(&wm8994->mic_work) in wm1811_jackdet_irq().
Fixes: c0cc3f166525 ("ASoC: wm8994: Allow a delay between jack insertion and microphone detect")
Signed-off-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
---
sound/soc/codecs/wm8994.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/sound/soc/codecs/wm8994.c b/sound/soc/codecs/wm8994.c
index d3cfd3788f2a..f810135e28d0 100644
--- a/sound/soc/codecs/wm8994.c
+++ b/sound/soc/codecs/wm8994.c
@@ -3853,7 +3853,12 @@ static irqreturn_t wm1811_jackdet_irq(int irq, void *data)
} else {
dev_dbg(component->dev, "Jack not detected\n");
+ /* Release wm8994->accdet_lock to avoid deadlock:
+ * cancel_delayed_work_sync() takes wm8994->mic_work internal
+ * lock and wm1811_mic_work takes wm8994->accdet_lock */
+ mutex_unlock(&wm8994->accdet_lock);
cancel_delayed_work_sync(&wm8994->mic_work);
+ mutex_lock(&wm8994->accdet_lock);
snd_soc_component_update_bits(component, WM8958_MICBIAS2,
WM8958_MICB2_DISCH, WM8958_MICB2_DISCH);
--
2.38.1
