From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752332AbbASJwt (ORCPT ); Mon, 19 Jan 2015 04:52:49 -0500 Received: from cantor2.suse.de ([195.135.220.15]:50648 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751667AbbASJws (ORCPT ); Mon, 19 Jan 2015 04:52:48 -0500 Date: Mon, 19 Jan 2015 10:52:46 +0100 Message-ID: From: Takashi Iwai To: Jiri Slaby Cc: linux-kernel@vger.kernel.org, Jaroslav Kysela , alsa-devel@alsa-project.org Subject: Re: [PATCH 2/3] sound: dummy, use del_timer_sync In-Reply-To: <1421660576-8435-2-git-send-email-jslaby@suse.cz> References: <1421660576-8435-1-git-send-email-jslaby@suse.cz> <1421660576-8435-2-git-send-email-jslaby@suse.cz> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI/1.14.6 (Maruoka) FLIM/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL/10.8 Emacs/24.4 (x86_64-suse-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI 1.14.6 - "Maruoka") Content-Type: text/plain; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org At Mon, 19 Jan 2015 10:42:55 +0100, Jiri Slaby wrote: > > Wait for the timer to really quit, not only by ensuring it is not in > the critical section. > > BTW the spin_lock in here does not disable BH, so that it could > deadlock. The stop function is called from the PCM trigger callback which is irq-disabled. So, you can't use del_timer_sync() here. thanks, Takashi > > Signed-off-by: Jiri Slaby > Cc: Jaroslav Kysela > Cc: Takashi Iwai > Cc: alsa-devel@alsa-project.org > --- > sound/drivers/dummy.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/sound/drivers/dummy.c b/sound/drivers/dummy.c > index d11baaf0f0b4..6d6bf4093583 100644 > --- a/sound/drivers/dummy.c > +++ b/sound/drivers/dummy.c > @@ -281,9 +281,9 @@ static int dummy_systimer_start(struct snd_pcm_substream *substream) > static int dummy_systimer_stop(struct snd_pcm_substream *substream) > { > struct dummy_systimer_pcm *dpcm = substream->runtime->private_data; > - spin_lock(&dpcm->lock); > - del_timer(&dpcm->timer); > - spin_unlock(&dpcm->lock); > + > + del_timer_sync(&dpcm->timer); > + > return 0; > } > > -- > 2.2.1 >