ASoC: rt5645: Fix errorenous cleanup order

There is a logic error when removing rt5645 device as the function
rt5645_i2c_remove() first cancel the &rt5645->jack_detect_work and
delete the &rt5645->btn_check_timer latter. However, since the timer
handler rt5645_btn_check_callback() will re-queue the jack_detect_work,
this cleanup order is buggy.

That is, once the del_timer_sync in rt5645_i2c_remove is concurrently
run with the rt5645_btn_check_callback, the canceled jack_detect_work
will be rescheduled again, leading to possible use-after-free.

This patch fix the issue by placing the del_timer_sync function before
the cancel_delayed_work_sync.

Signed-off-by: Lin Ma <linma@zju.edu.cn>
Link: https://lore.kernel.org/r/20220516092035.28283-1-linma@zju.edu.cn
Signed-off-by: Mark Brown <broonie@kernel.org>

diff --git a/sound/soc/codecs/rt5645.c b/sound/soc/codecs/rt5645.c
index ccdea23..507aba8 100644 (file)
--- a/sound/soc/codecs/rt5645.c
+++ b/sound/soc/codecs/rt5645.c
@@ -4153,9 +4153,14 @@ static int rt5645_i2c_remove(struct i2c_client *i2c)
        if (i2c->irq)
                free_irq(i2c->irq, rt5645);
 
+       /*
+        * Since the rt5645_btn_check_callback() can queue jack_detect_work,
+        * the timer need to be delted first
+        */
+       del_timer_sync(&rt5645->btn_check_timer);
+
        cancel_delayed_work_sync(&rt5645->jack_detect_work);
        cancel_delayed_work_sync(&rt5645->rcclock_work);
-       del_timer_sync(&rt5645->btn_check_timer);
 
        regulator_bulk_disable(ARRAY_SIZE(rt5645->supplies), rt5645->supplies);