On Fri, Dec 09, 2022 at 10:16:57AM +0100, Marek Szyprowski wrote:
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@samsung.com
Acked-by: Charles Keepax ckeepax@opensource.cirrus.com
Thanks, Charles