From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756111Ab2ILXeQ (ORCPT ); Wed, 12 Sep 2012 19:34:16 -0400 Received: from mail-ob0-f174.google.com ([209.85.214.174]:37074 "EHLO mail-ob0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756047Ab2ILXeF (ORCPT ); Wed, 12 Sep 2012 19:34:05 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg KH , Takashi Iwai Subject: [ 059/108] ALSA: usb-audio: Fix scheduling-while-atomic bug in PCM capture stream Date: Wed, 12 Sep 2012 16:28:57 -0700 Message-Id: <20120912232456.729849839@linuxfoundation.org> X-Mailer: git-send-email 1.7.10.1.362.g242cab3 In-Reply-To: <20120912232450.500619493@linuxfoundation.org> References: <20120912232816.GA1655@kroah.com> <20120912232450.500619493@linuxfoundation.org> User-Agent: quilt/0.60-2.1.2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Greg KH 3.5-stable review patch. If anyone has any objections, please let me know. ------------------ From: Takashi Iwai commit e9ba389c5ffc4dd29dfe17e00e48877302111135 upstream. A PCM capture stream on usb-audio causes a scheduling-while-atomic BUG, as reported in the bugzilla entry below. It's because snd_usb_endpoint_start() is called at first at trigger START for a capture stream, and this function contains the left-over EP deactivation codes. The problem doesn't happen for a playback stream because the function is called at PCM prepare time, which can sleep. This patch fixes the BUG by moving the EP deactivation code into the PCM prepare callback. Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=46011 Signed-off-by: Takashi Iwai Signed-off-by: Greg Kroah-Hartman --- sound/usb/endpoint.c | 4 ---- sound/usb/pcm.c | 3 +++ 2 files changed, 3 insertions(+), 4 deletions(-) --- a/sound/usb/endpoint.c +++ b/sound/usb/endpoint.c @@ -821,10 +821,6 @@ int snd_usb_endpoint_start(struct snd_us if (++ep->use_count != 1) return 0; - /* just to be sure */ - deactivate_urbs(ep, 0, 1); - wait_clear_urbs(ep); - ep->active_mask = 0; ep->unlink_mask = 0; ep->phase = 0; --- a/sound/usb/pcm.c +++ b/sound/usb/pcm.c @@ -544,6 +544,9 @@ static int snd_usb_pcm_prepare(struct sn subs->last_frame_number = 0; runtime->delay = 0; + /* clear the pending deactivation on the target EPs */ + deactivate_endpoints(subs); + /* for playback, submit the URBs now; otherwise, the first hwptr_done * updates for all URBs would happen at the same time when starting */ if (subs->direction == SNDRV_PCM_STREAM_PLAYBACK)