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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 05B03C432C0 for ; Fri, 22 Nov 2019 19:51:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C29ED20726 for ; Fri, 22 Nov 2019 19:51:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1574452276; bh=vu3BNhVtu/OVi6DJ35glNw192nWK9hfAbzabOyJgl4w=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=PUL4n4IyXmv/QW2sRAqhqMf+dqIxlZ0oAbklUpw6xfdQcevc5VbH0Q6x0URnM99Z+ Z/3YKcP7FCr6rvScToBvfDeG7WniUt3/S8GR56Wfl3k7pDAWfzFUlI/ZunhYt7zQxL KSRNcnBDikVbDnrwjMvEXG+86WfAvPlyFOSDpJd4= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727783AbfKVTuO (ORCPT ); Fri, 22 Nov 2019 14:50:14 -0500 Received: from mail.kernel.org ([198.145.29.99]:50612 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727727AbfKVTuG (ORCPT ); Fri, 22 Nov 2019 14:50:06 -0500 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id B7A542084D; Fri, 22 Nov 2019 19:50:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1574452206; bh=vu3BNhVtu/OVi6DJ35glNw192nWK9hfAbzabOyJgl4w=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Tlq4Gs0c1zyTqLDLZL9jJR6lWtB2ErPwTVdQLLMgoZL5BqPTKMeyfJ87KNnngdHyc 7Hu3hhd0WM1KwH5WTA7WHj77VM06xnXK6dsRlyE+z3tLlPrIWnL9Q/0QETMRv9X5VN Gq5cPFlyEsWk99nkVTch0Ayff755dfL+Q7PaHO74= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: paulhsia , Takashi Iwai , Sasha Levin , alsa-devel@alsa-project.org Subject: [PATCH AUTOSEL 4.9 07/13] ALSA: pcm: Fix stream lock usage in snd_pcm_period_elapsed() Date: Fri, 22 Nov 2019 14:49:52 -0500 Message-Id: <20191122194958.24926-7-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20191122194958.24926-1-sashal@kernel.org> References: <20191122194958.24926-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore 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 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