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,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 D98F7C2D0C1 for ; Thu, 19 Dec 2019 18:42:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B0AB6222C2 for ; Thu, 19 Dec 2019 18:42:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1576780934; bh=vu3BNhVtu/OVi6DJ35glNw192nWK9hfAbzabOyJgl4w=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=aP46iOUHH+SS+i5P277UlLW38qOPQU0vRr2Cw2NP+6iXjRyE0BTheuo9bpwdyrt0F KJ2EDFLHz74PPx7jmKjGMfrrR6QVXllC/wWavGPBG5woFqBl1GCdmiEldcjd66Xc1F stjl+vCSFsIPu/twK5R754rGNWOuAsrorZe+WD2M= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728633AbfLSSmM (ORCPT ); Thu, 19 Dec 2019 13:42:12 -0500 Received: from mail.kernel.org ([198.145.29.99]:33258 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728647AbfLSSmL (ORCPT ); Thu, 19 Dec 2019 13:42:11 -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 EB88E206D7; Thu, 19 Dec 2019 18:42:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1576780931; bh=vu3BNhVtu/OVi6DJ35glNw192nWK9hfAbzabOyJgl4w=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=PVp/clR4PjWlkU35IJZJI0a4GQsFfglwDLfMj215Vyolqlb8Vq+3Cb41F9bV/q1zh Pt7xZCL8rh9Y5aAdOSbi6HW8ApoI51qa75vICso7WcBIfzBS8FF5BUrQn52yEuFPio WnjuEsIUwpFV4f0eEfg+mUP+5O3jlt252/7+3Qao= 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 4.9 014/199] ALSA: pcm: Fix stream lock usage in snd_pcm_period_elapsed() Date: Thu, 19 Dec 2019 19:31:36 +0100 Message-Id: <20191219183215.551455232@linuxfoundation.org> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20191219183214.629503389@linuxfoundation.org> References: <20191219183214.629503389@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@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 3acb373674c37..f09ae7efc6957 100644 --- a/sound/core/pcm_lib.c +++ b/sound/core/pcm_lib.c @@ -1877,11 +1877,14 @@ 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; @@ -1892,6 +1895,7 @@ 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); } -- 2.20.1