From patchwork Wed Nov 5 14:21:07 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Takashi Iwai X-Patchwork-Id: 5234261 X-Patchwork-Delegate: tiwai@suse.de Return-Path: X-Original-To: patchwork-alsa-devel@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 1BDD89F295 for ; Wed, 5 Nov 2014 14:22:02 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 2CF8420172 for ; Wed, 5 Nov 2014 14:22:01 +0000 (UTC) Received: from alsa0.perex.cz (alsa0.perex.cz [77.48.224.243]) by mail.kernel.org (Postfix) with ESMTP id C4BFC20108 for ; Wed, 5 Nov 2014 14:21:59 +0000 (UTC) Received: by alsa0.perex.cz (Postfix, from userid 1000) id D0C2C264F0A; Wed, 5 Nov 2014 15:21:58 +0100 (CET) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Spam-Level: X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_NONE, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 Received: from alsa0.perex.cz (localhost [IPv6:::1]) by alsa0.perex.cz (Postfix) with ESMTP id C59F2264F40; Wed, 5 Nov 2014 15:21:41 +0100 (CET) X-Original-To: alsa-devel@alsa-project.org Delivered-To: alsa-devel@alsa-project.org Received: by alsa0.perex.cz (Postfix, from userid 1000) id 11633264F45; Wed, 5 Nov 2014 15:21:36 +0100 (CET) Received: from mx2.suse.de (cantor2.suse.de [195.135.220.15]) by alsa0.perex.cz (Postfix) with ESMTP id 700E62625D7 for ; Wed, 5 Nov 2014 15:21:08 +0100 (CET) Received: from relay2.suse.de (charybdis-ext.suse.de [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 53B82ACEE for ; Wed, 5 Nov 2014 14:21:08 +0000 (UTC) From: Takashi Iwai To: alsa-devel@alsa-project.org Date: Wed, 5 Nov 2014 15:21:07 +0100 Message-Id: <1415197267-30291-1-git-send-email-tiwai@suse.de> X-Mailer: git-send-email 2.1.3 Subject: [alsa-devel] [PATCH] ALSA: usb-audio: Fix device_del() sysfs warnings at disconnect X-BeenThere: alsa-devel@alsa-project.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: "Alsa-devel mailing list for ALSA developers - http://www.alsa-project.org" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: alsa-devel-bounces@alsa-project.org Sender: alsa-devel-bounces@alsa-project.org X-Virus-Scanned: ClamAV using ClamSMTP Some USB-audio devices show weird sysfs warnings at disconnecting the devices, e.g. usb 1-3: USB disconnect, device number 3 ------------[ cut here ]------------ WARNING: CPU: 0 PID: 973 at fs/sysfs/group.c:216 device_del+0x39/0x180() sysfs group ffffffff8183df40 not found for kobject 'midiC1D0' Call Trace: [] ? dump_stack+0x49/0x71 [] ? warn_slowpath_common+0x82/0xb0 [] ? warn_slowpath_fmt+0x45/0x50 [] ? device_del+0x39/0x180 [] ? device_unregister+0x9/0x20 [] ? device_destroy+0x34/0x40 [] ? snd_unregister_device+0x7f/0xd0 [snd] [] ? snd_rawmidi_dev_disconnect+0xce/0x100 [snd_rawmidi] [] ? snd_device_disconnect+0x62/0x90 [snd] [] ? snd_device_disconnect_all+0x3c/0x60 [snd] [] ? snd_card_disconnect+0x124/0x1a0 [snd] [] ? usb_audio_disconnect+0x88/0x1c0 [snd_usb_audio] [] ? usb_unbind_interface+0x5e/0x1b0 [usbcore] [] ? __device_release_driver+0x79/0xf0 [] ? device_release_driver+0x25/0x40 [] ? bus_remove_device+0xf1/0x130 [] ? device_del+0x109/0x180 [] ? usb_disable_device+0x95/0x1f0 [usbcore] [] ? usb_disconnect+0x8f/0x190 [usbcore] [] ? hub_thread+0x539/0x13a0 [usbcore] [] ? sched_clock_local+0x15/0x80 [] ? sched_clock_cpu+0xb8/0xd0 [] ? bit_waitqueue+0xb0/0xb0 [] ? usb_port_resume+0x430/0x430 [usbcore] [] ? usb_port_resume+0x430/0x430 [usbcore] [] ? kthread+0xce/0xf0 [] ? kthread_create_on_node+0x1c0/0x1c0 [] ? ret_from_fork+0x7c/0xb0 [] ? kthread_create_on_node+0x1c0/0x1c0 ---[ end trace 40b1928d1136b91e ]--- This comes from the fact that usb-audio driver may receive the disconnect callback multiple times, per each usb interface. When a device has both audio and midi interfaces, it gets called twice, and currently the driver tries to release resources at the last call. At this point, the first parent interface has been already deleted, thus deleting a child of the first parent hits such a warning. For fixing this problem, we need to call snd_card_disconnect() and cancel pending operations at the very first disconnect while the release of the whole objects waits until the last disconnect call. Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=80931 Reported-and-tested-by: Tomas Gayoso Cc: Signed-off-by: Takashi Iwai --- sound/usb/card.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/sound/usb/card.c b/sound/usb/card.c index 7ecd0e8a5c51..f61ebb17cc64 100644 --- a/sound/usb/card.c +++ b/sound/usb/card.c @@ -591,18 +591,19 @@ static void snd_usb_audio_disconnect(struct usb_device *dev, { struct snd_card *card; struct list_head *p; + bool was_shutdown; if (chip == (void *)-1L) return; card = chip->card; down_write(&chip->shutdown_rwsem); + was_shutdown = chip->shutdown; chip->shutdown = 1; up_write(&chip->shutdown_rwsem); mutex_lock(®ister_mutex); - chip->num_interfaces--; - if (chip->num_interfaces <= 0) { + if (!was_shutdown) { struct snd_usb_endpoint *ep; snd_card_disconnect(card); @@ -622,6 +623,10 @@ static void snd_usb_audio_disconnect(struct usb_device *dev, list_for_each(p, &chip->mixer_list) { snd_usb_mixer_disconnect(p); } + } + + chip->num_interfaces--; + if (chip->num_interfaces <= 0) { usb_chip[chip->index] = NULL; mutex_unlock(®ister_mutex); snd_card_free_when_closed(card);