6.12-stable review patch. If anyone has any objections, please let me know.
------------------
From: Takashi Iwai <tiwai@xxxxxxx>
[ Upstream commit dafb28f02be407e07a6f679e922a626592b481b0 ]
The USB disconnect callback is supposed to be short and not too-long
waiting. OTOH, the current code uses snd_card_free() at
disconnection, but this waits for the close of all used fds, hence it
can take long. It eventually blocks the upper layer USB ioctls, which
may trigger a soft lockup.
An easy workaround is to replace snd_card_free() with
snd_card_free_when_closed(). This variant returns immediately while
the release of resources is done asynchronously by the card device
release at the last close.
Fixes: 230cd5e24853 ("[ALSA] prevent oops & dead keyboard on usb unplugging while the device is be ing used")
Reported-by: syzbot+73582d08864d8268b6fd@xxxxxxxxxxxxxxxxxxxxxxxxx
Closes: https://syzkaller.appspot.com/bug?extid=73582d08864d8268b6fd
Signed-off-by: Takashi Iwai <tiwai@xxxxxxx>
Link: https://patch.msgid.link/20241113111042.15058-2-tiwai@xxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
sound/usb/usx2y/usbusx2y.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/sound/usb/usx2y/usbusx2y.c b/sound/usb/usx2y/usbusx2y.c
index 2f9cede242b3a..5f81c68fd42b6 100644
--- a/sound/usb/usx2y/usbusx2y.c
+++ b/sound/usb/usx2y/usbusx2y.c
@@ -422,7 +422,7 @@ static void snd_usx2y_disconnect(struct usb_interface *intf)
}
if (usx2y->us428ctls_sharedmem)
wake_up(&usx2y->us428ctls_wait_queue_head);
- snd_card_free(card);
+ snd_card_free_when_closed(card);
}
static int snd_usx2y_probe(struct usb_interface *intf,
--
2.43.0
