[PATCH v2] ALSA: control: Avoid WARN() for symlink errors

[Takashi Iwai <tiwai@xxxxxxx>]

Using WARN() for showing the error of symlink creations don't give
more information than telling that something goes wrong, since the
usual code path is a lregister callback from each control element
creation.  More badly, the use of WARN() rather confuses fuzzer as if
it were serious issues.

This patch downgrades the warning messages to use the normal dev_err()
instead of WARN().  For making it clearer, add the function name to
the prefix, too.

Fixes: a135dfb5de15 ("ALSA: led control - add sysfs kcontrol LED marking layer")
Reported-by: syzbot+4e7919b09c67ffd198ae@xxxxxxxxxxxxxxxxxxxxxxxxx
Closes: https://lore.kernel.org/675664c7.050a0220.a30f1.018c.GAE@xxxxxxxxxx
Signed-off-by: Takashi Iwai <tiwai@xxxxxxx>
---
v1->v2: Use dev_err() with the card object instead of pr_warn()

 sound/core/control_led.c | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/sound/core/control_led.c b/sound/core/control_led.c
index 65a1ebe87776..e33dfcf863cf 100644
--- a/sound/core/control_led.c
+++ b/sound/core/control_led.c
@@ -668,10 +668,16 @@ static void snd_ctl_led_sysfs_add(struct snd_card *card)
 			goto cerr;
 		led->cards[card->number] = led_card;
 		snprintf(link_name, sizeof(link_name), "led-%s", led->name);
-		WARN(sysfs_create_link(&card->ctl_dev->kobj, &led_card->dev.kobj, link_name),
-			"can't create symlink to controlC%i device\n", card->number);
-		WARN(sysfs_create_link(&led_card->dev.kobj, &card->card_dev.kobj, "card"),
-			"can't create symlink to card%i\n", card->number);
+		if (sysfs_create_link(&card->ctl_dev->kobj, &led_card->dev.kobj,
+				      link_name))
+			dev_err(card->dev,
+				"%s: can't create symlink to controlC%i device\n",
+				 __func__, card->number);
+		if (sysfs_create_link(&led_card->dev.kobj, &card->card_dev.kobj,
+				      "card"))
+			dev_err(card->dev,
+				"%s: can't create symlink to card%i\n",
+				__func__, card->number);
 
 		continue;
 cerr:
-- 
2.43.0