Oops with "ALSA: jack: implement software jack injection via debugfs"

[Takashi Iwai]

On Tue, 02 Feb 2021 17:30:36 +0100,
Chris Wilson wrote:
> 
> commit 2d670ea2bd53 ("ALSA: jack: implement software jack injection via
> debugfs") is causing issues for our CI as we see a use-after-free on
> module unload (on all machines):
> 
> https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_9715/fi-skl-6700k2/pstore0-1612277467_Oops_1.txt

Could you try the patch below?  The unload test was completely
forgotten.


thanks,

Takashi

-- 8< --
From: Takashi Iwai <tiwai at suse.de>
Subject: [PATCH] ALSA: core: Fix the debugfs removal at snd_card_free()

The debugfs_remove() call should have been done at the right place
before the card object gets freed.

Fixes: 2d670ea2bd53 ("ALSA: jack: implement software jack injection via debugfs")
Signed-off-by: Takashi Iwai <tiwai at suse.de>
---
 sound/core/init.c | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/sound/core/init.c b/sound/core/init.c
index d4e78b176793..84b573e9c1f9 100644
--- a/sound/core/init.c
+++ b/sound/core/init.c
@@ -487,6 +487,10 @@ static int snd_card_do_free(struct snd_card *card)
 		dev_warn(card->dev, "unable to free card info\n");
 		/* Not fatal error */
 	}
+#ifdef CONFIG_SND_DEBUG
+	debugfs_remove(card->debugfs_root);
+	card->debugfs_root = NULL;
+#endif
 	if (card->release_completion)
 		complete(card->release_completion);
 	kfree(card);
@@ -537,11 +541,6 @@ int snd_card_free(struct snd_card *card)
 	/* wait, until all devices are ready for the free operation */
 	wait_for_completion(&released);
 
-#ifdef CONFIG_SND_DEBUG
-	debugfs_remove(card->debugfs_root);
-	card->debugfs_root = NULL;
-#endif
-
 	return 0;
 }
 EXPORT_SYMBOL(snd_card_free);
-- 
2.26.2