From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5B3E6C4CEC9 for ; Wed, 18 Sep 2019 09:41:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 342E4218AF for ; Wed, 18 Sep 2019 09:41:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728120AbfIRJla (ORCPT ); Wed, 18 Sep 2019 05:41:30 -0400 Received: from relay3-d.mail.gandi.net ([217.70.183.195]:50455 "EHLO relay3-d.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725909AbfIRJl3 (ORCPT ); Wed, 18 Sep 2019 05:41:29 -0400 X-Originating-IP: 86.207.98.53 Received: from localhost (aclermont-ferrand-651-1-259-53.w86-207.abo.wanadoo.fr [86.207.98.53]) (Authenticated sender: gregory.clement@bootlin.com) by relay3-d.mail.gandi.net (Postfix) with ESMTPSA id D54B06000C; Wed, 18 Sep 2019 09:41:27 +0000 (UTC) From: Gregory CLEMENT To: Codrin Ciubotariu , Liam Girdwood , Mark Brown , alsa-devel@alsa-project.org, linux-kernel@vger.kernel.org Cc: Nicolas Ferre , Alexandre Belloni , Ludovic Desroches , linux-arm-kernel@lists.infradead.org, Gregory CLEMENT Subject: [PATCH] ASoC: atmel_ssc_dai: Remove wrong spinlock usage Date: Wed, 18 Sep 2019 11:41:14 +0200 Message-Id: <20190918094114.15867-1-gregory.clement@bootlin.com> X-Mailer: git-send-email 2.23.0 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org A potential bug was reported in the email "[BUG] atmel_ssc_dai: a possible sleep-in-atomic bug in atmel_ssc_shutdown"[1] Indeed in the function atmel_ssc_shutdown() free_irq() was called in a critical section protected by spinlock. However this spinlock is only used in atmel_ssc_shutdown() and atmel_ssc_startup() functions. After further analysis, it occurred that the call to these function are already protected by mutex used on the calling functions. Then we can remove the spinlock which will fix this bug as a side effect. Thanks to this patch the following message disappears: "BUG: sleeping function called from invalid context at kernel/locking/mutex.c:909" [1]: https://www.spinics.net/lists/alsa-devel/msg71286.html Signed-off-by: Gregory CLEMENT --- sound/soc/atmel/atmel_ssc_dai.c | 7 ------- 1 file changed, 7 deletions(-) diff --git a/sound/soc/atmel/atmel_ssc_dai.c b/sound/soc/atmel/atmel_ssc_dai.c index 6f89483ac88c..365957e86419 100644 --- a/sound/soc/atmel/atmel_ssc_dai.c +++ b/sound/soc/atmel/atmel_ssc_dai.c @@ -116,19 +116,16 @@ static struct atmel_pcm_dma_params ssc_dma_params[NUM_SSC_DEVICES][2] = { static struct atmel_ssc_info ssc_info[NUM_SSC_DEVICES] = { { .name = "ssc0", - .lock = __SPIN_LOCK_UNLOCKED(ssc_info[0].lock), .dir_mask = SSC_DIR_MASK_UNUSED, .initialized = 0, }, { .name = "ssc1", - .lock = __SPIN_LOCK_UNLOCKED(ssc_info[1].lock), .dir_mask = SSC_DIR_MASK_UNUSED, .initialized = 0, }, { .name = "ssc2", - .lock = __SPIN_LOCK_UNLOCKED(ssc_info[2].lock), .dir_mask = SSC_DIR_MASK_UNUSED, .initialized = 0, }, @@ -317,13 +314,11 @@ static int atmel_ssc_startup(struct snd_pcm_substream *substream, snd_soc_dai_set_dma_data(dai, substream, dma_params); - spin_lock_irq(&ssc_p->lock); if (ssc_p->dir_mask & dir_mask) { spin_unlock_irq(&ssc_p->lock); return -EBUSY; } ssc_p->dir_mask |= dir_mask; - spin_unlock_irq(&ssc_p->lock); return 0; } @@ -355,7 +350,6 @@ static void atmel_ssc_shutdown(struct snd_pcm_substream *substream, dir_mask = 1 << dir; - spin_lock_irq(&ssc_p->lock); ssc_p->dir_mask &= ~dir_mask; if (!ssc_p->dir_mask) { if (ssc_p->initialized) { @@ -369,7 +363,6 @@ static void atmel_ssc_shutdown(struct snd_pcm_substream *substream, ssc_p->cmr_div = ssc_p->tcmr_period = ssc_p->rcmr_period = 0; ssc_p->forced_divider = 0; } - spin_unlock_irq(&ssc_p->lock); /* Shutdown the SSC clock. */ pr_debug("atmel_ssc_dai: Stopping clock\n"); -- 2.23.0