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[2620:137:e000::1:20]) by mx.google.com with ESMTP id z20-20020a05640240d400b0045807f73ad5si3779739edb.570.2022.10.24.05.17.22; Mon, 24 Oct 2022 05:17:46 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@linuxfoundation.org header.s=korg header.b=REMtXv2z; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=linuxfoundation.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232797AbiJXMKk (ORCPT + 99 others); Mon, 24 Oct 2022 08:10:40 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38684 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232929AbiJXMJM (ORCPT ); Mon, 24 Oct 2022 08:09:12 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 792D27F127; Mon, 24 Oct 2022 04:52:25 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 1B82EB81186; Mon, 24 Oct 2022 11:42:10 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6572DC43470; Mon, 24 Oct 2022 11:42:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1666611728; bh=bZwGPZDTogpLUxzxQ5yHMwfGBVlcNdR2myoMTG7FLZA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=REMtXv2zBbpO2bzvCRjMN0pPoFWnE9s11ctN5z+5Rr1FdWlVIwjHnQ5FTmDpBstu8 plG8mKpWDse6M3map0RW6zyw37ysRYh4bYmBqXihP7MfyoY8/tRKu6akXXqdTtMyuA m0/kpK3UtYTrtNuKM8xPYlJT7BkCFObEASKYXRNQ= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Andreas Pape , Eugeniu Rosca , Takashi Iwai , Sasha Levin Subject: [PATCH 4.9 081/159] ALSA: dmaengine: increment buffer pointer atomically Date: Mon, 24 Oct 2022 13:30:35 +0200 Message-Id: <20221024112952.390218748@linuxfoundation.org> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221024112949.358278806@linuxfoundation.org> References: <20221024112949.358278806@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 X-Spam-Status: No, score=-7.6 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_HI, SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1747571301511230753?= X-GMAIL-MSGID: =?utf-8?q?1747571301511230753?= From: Andreas Pape [ Upstream commit d1c442019594692c64a70a86ad88eb5b6db92216 ] Setting pointer and afterwards checking for wraparound leads to the possibility of returning the inconsistent pointer position. This patch increments buffer pointer atomically to avoid this issue. Fixes: e7f73a1613567a ("ASoC: Add dmaengine PCM helper functions") Signed-off-by: Andreas Pape Signed-off-by: Eugeniu Rosca Link: https://lore.kernel.org/r/1664211493-11789-1-git-send-email-erosca@de.adit-jv.com Signed-off-by: Takashi Iwai Signed-off-by: Sasha Levin --- sound/core/pcm_dmaengine.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/sound/core/pcm_dmaengine.c b/sound/core/pcm_dmaengine.c index 8eb58c709b14..6f6da1128edc 100644 --- a/sound/core/pcm_dmaengine.c +++ b/sound/core/pcm_dmaengine.c @@ -139,12 +139,14 @@ EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_set_config_from_dai_data); static void dmaengine_pcm_dma_complete(void *arg) { + unsigned int new_pos; struct snd_pcm_substream *substream = arg; struct dmaengine_pcm_runtime_data *prtd = substream_to_prtd(substream); - prtd->pos += snd_pcm_lib_period_bytes(substream); - if (prtd->pos >= snd_pcm_lib_buffer_bytes(substream)) - prtd->pos = 0; + new_pos = prtd->pos + snd_pcm_lib_period_bytes(substream); + if (new_pos >= snd_pcm_lib_buffer_bytes(substream)) + new_pos = 0; + prtd->pos = new_pos; snd_pcm_period_elapsed(substream); }