drm/bridge: adv7511: fix crash on irq during probe

Moved IRQ registration down to end of adv7511_probe().

If an IRQ already is pending during adv7511_probe
(before adv7511_cec_init) then cec_received_msg_ts
could crash using uninitialized data:

    Unable to handle kernel read from unreadable memory at virtual address 00000000000003d5
    Internal error: Oops: 96000004 [#1] PREEMPT_RT SMP
    Call trace:
     cec_received_msg_ts+0x48/0x990 [cec]
     adv7511_cec_irq_process+0x1cc/0x308 [adv7511]
     adv7511_irq_process+0xd8/0x120 [adv7511]
     adv7511_irq_handler+0x1c/0x30 [adv7511]
     irq_thread_fn+0x30/0xa0
     irq_thread+0x14c/0x238
     kthread+0x190/0x1a8

Fixes: 3b1b975003e4 ("drm: adv7511/33: add HDMI CEC support")
Signed-off-by: Mads Bligaard Nielsen <bli@bang-olufsen.dk>
Signed-off-by: Alvin Šipraga <alsi@bang-olufsen.dk>
Reviewed-by: Robert Foss <rfoss@kernel.org>
Signed-off-by: Robert Foss <rfoss@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20240219-adv7511-cec-irq-crash-fix-v2-1-245e53c4b96f@bang-olufsen.dk

diff --git a/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c b/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
index 1e40d451ce8c275b345a72092a9658a6130ca34a..b5518ff971657119e731e58990cf0a06a887a09d 100644 (file)
--- a/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
+++ b/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
@@ -1290,17 +1290,6 @@ static int adv7511_probe(struct i2c_client *i2c)
 
        INIT_WORK(&adv7511->hpd_work, adv7511_hpd_work);
 
-       if (i2c->irq) {
-               init_waitqueue_head(&adv7511->wq);
-
-               ret = devm_request_threaded_irq(dev, i2c->irq, NULL,
-                                               adv7511_irq_handler,
-                                               IRQF_ONESHOT, dev_name(dev),
-                                               adv7511);
-               if (ret)
-                       goto err_unregister_cec;
-       }
-
        adv7511_power_off(adv7511);
 
        i2c_set_clientdata(i2c, adv7511);
@@ -1324,6 +1313,17 @@ static int adv7511_probe(struct i2c_client *i2c)
 
        adv7511_audio_init(dev, adv7511);
 
+       if (i2c->irq) {
+               init_waitqueue_head(&adv7511->wq);
+
+               ret = devm_request_threaded_irq(dev, i2c->irq, NULL,
+                                               adv7511_irq_handler,
+                                               IRQF_ONESHOT, dev_name(dev),
+                                               adv7511);
+               if (ret)
+                       goto err_unregister_audio;
+       }
+
        if (adv7511->info->has_dsi) {
                ret = adv7533_attach_dsi(adv7511);
                if (ret)