5.4-stable review patch. If anyone has any objections, please let me know.
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From: Takashi Iwai tiwai@suse.de
[ Upstream commit b7df09bb348016943f56b09dcaafe221e3f73947 ]
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.
The loop of us122l->mmap_count check is dropped as well. The check is useless for the asynchronous operation with *_when_closed().
Fixes: 030a07e44129 ("ALSA: Add USB US122L driver") Signed-off-by: Takashi Iwai tiwai@suse.de Link: https://patch.msgid.link/20241113111042.15058-3-tiwai@suse.de Signed-off-by: Sasha Levin sashal@kernel.org --- sound/usb/usx2y/us122l.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-)
diff --git a/sound/usb/usx2y/us122l.c b/sound/usb/usx2y/us122l.c index e82c5236482df..eb7e57c4a7fdb 100644 --- a/sound/usb/usx2y/us122l.c +++ b/sound/usb/usx2y/us122l.c @@ -636,10 +636,7 @@ static void snd_us122l_disconnect(struct usb_interface *intf) usb_put_intf(usb_ifnum_to_if(us122l->dev, 1)); usb_put_dev(us122l->dev);
- while (atomic_read(&us122l->mmap_count)) - msleep(500); - - snd_card_free(card); + snd_card_free_when_closed(card); }
static int snd_us122l_suspend(struct usb_interface *intf, pm_message_t message)