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=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,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 F10CCC43603 for ; Wed, 11 Dec 2019 15:16:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BBF4124671 for ; Wed, 11 Dec 2019 15:16:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1576077398; bh=PgmHLsBySMD/WAnnTimLDpSm6vxvYajJ38PYZvgkUhw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=Q2Wk53aGimGKs1gRJBTOBXocucfUXJIPafj+ZVeZghvD5M7Y5Nz0I20Pek5pv+GtP xT4yAa5PBHWP6B9QxfbZ+gQE7aksa+v6PbokyfUhm5LAmiEVykQw+pqfh9pKa5ZOQu +/pgS6S0zN9/qa1ph3/4eQAm1EAzvIhhf0Zy7Tnc= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731703AbfLKPQg (ORCPT ); Wed, 11 Dec 2019 10:16:36 -0500 Received: from mail.kernel.org ([198.145.29.99]:43714 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729948AbfLKPQc (ORCPT ); Wed, 11 Dec 2019 10:16:32 -0500 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 2FBBD22B48; Wed, 11 Dec 2019 15:16:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1576077391; bh=PgmHLsBySMD/WAnnTimLDpSm6vxvYajJ38PYZvgkUhw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=UMaPxVIBIWxeTZqJGgvYS16fZ4JxCp4KvkZO31vDQQjO4tcvSFuOFocyK3i3qHQ3o BrjAv7tHphpEgpzbyggI+PCMjmNH5fdXcrd1DE5iQeL1jH0MZD/J7KHJKXXkh+sq77 9HnFAm2fRwMgHIRJlhFx+JawgACxy/bW1IGdJzrE= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, paulhsia , Takashi Iwai , Sasha Levin Subject: [PATCH 4.19 021/243] ALSA: pcm: Fix stream lock usage in snd_pcm_period_elapsed() Date: Wed, 11 Dec 2019 16:03:03 +0100 Message-Id: <20191211150340.396129292@linuxfoundation.org> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20191211150339.185439726@linuxfoundation.org> References: <20191211150339.185439726@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: paulhsia [ Upstream commit f5cdc9d4003a2f66ea57b3edd3e04acc2b1a4439 ] If the nullity check for `substream->runtime` is outside of the lock region, it is possible to have a null runtime in the critical section if snd_pcm_detach_substream is called right before the lock. Signed-off-by: paulhsia Link: https://lore.kernel.org/r/20191112171715.128727-2-paulhsia@chromium.org Signed-off-by: Takashi Iwai Signed-off-by: Sasha Levin --- sound/core/pcm_lib.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/sound/core/pcm_lib.c b/sound/core/pcm_lib.c index 4e6110d778bd2..ad52126d3d22e 100644 --- a/sound/core/pcm_lib.c +++ b/sound/core/pcm_lib.c @@ -1797,11 +1797,14 @@ void snd_pcm_period_elapsed(struct snd_pcm_substream *substream) struct snd_pcm_runtime *runtime; unsigned long flags; - if (PCM_RUNTIME_CHECK(substream)) + if (snd_BUG_ON(!substream)) return; - runtime = substream->runtime; snd_pcm_stream_lock_irqsave(substream, flags); + if (PCM_RUNTIME_CHECK(substream)) + goto _unlock; + runtime = substream->runtime; + if (!snd_pcm_running(substream) || snd_pcm_update_hw_ptr0(substream, 1) < 0) goto _end; @@ -1812,6 +1815,7 @@ void snd_pcm_period_elapsed(struct snd_pcm_substream *substream) #endif _end: kill_fasync(&runtime->fasync, SIGIO, POLL_IN); + _unlock: snd_pcm_stream_unlock_irqrestore(substream, flags); } EXPORT_SYMBOL(snd_pcm_period_elapsed); -- 2.20.1