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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 18454FA3746 for ; Mon, 24 Oct 2022 11:50:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231731AbiJXLuB (ORCPT ); Mon, 24 Oct 2022 07:50:01 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34800 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231855AbiJXLtG (ORCPT ); Mon, 24 Oct 2022 07:49:06 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4CF6B317FE; Mon, 24 Oct 2022 04:43:42 -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 dfw.source.kernel.org (Postfix) with ESMTPS id E9C2E6122D; Mon, 24 Oct 2022 11:40:07 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0398EC43470; Mon, 24 Oct 2022 11:40:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1666611607; bh=sM65ncKA0Fp2DSYemjydTSKTheS9f7SXxpox3tYAn2Y=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Bdci86HkMTQNhFJCfK2IB9/78Iuc3y9haI/6ZohFQR2THaKPdnylgwD5NgsxXgMJR dVAOLpoW2p55/Oxms6+gv4P3Rq4K7rmeBhdV9C/vpvREcywCBOT9+qJZGWzBI0pFtj E6mer7mBDPa4FURxM0IavjhcafPhcSkYiNa/VBms= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Takashi Iwai Subject: [PATCH 4.9 042/159] ALSA: rawmidi: Drop register_mutex in snd_rawmidi_free() Date: Mon, 24 Oct 2022 13:29:56 +0200 Message-Id: <20221024112950.915017843@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 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Takashi Iwai commit a70aef7982b012e86dfd39fbb235e76a21ae778a upstream. The register_mutex taken around the dev_unregister callback call in snd_rawmidi_free() may potentially lead to a mutex deadlock, when OSS emulation and a hot unplug are involved. Since the mutex doesn't protect the actual race (as the registration itself is already protected by another means), let's drop it. Link: https://lore.kernel.org/r/CAB7eexJP7w1B0mVgDF0dQ+gWor7UdkiwPczmL7pn91xx8xpzOA@mail.gmail.com Cc: Link: https://lore.kernel.org/r/20221011070147.7611-1-tiwai@suse.de Signed-off-by: Takashi Iwai Signed-off-by: Greg Kroah-Hartman --- sound/core/rawmidi.c | 2 -- 1 file changed, 2 deletions(-) --- a/sound/core/rawmidi.c +++ b/sound/core/rawmidi.c @@ -1633,10 +1633,8 @@ static int snd_rawmidi_free(struct snd_r snd_info_free_entry(rmidi->proc_entry); rmidi->proc_entry = NULL; - mutex_lock(®ister_mutex); if (rmidi->ops && rmidi->ops->dev_unregister) rmidi->ops->dev_unregister(rmidi); - mutex_unlock(®ister_mutex); snd_rawmidi_free_substreams(&rmidi->streams[SNDRV_RAWMIDI_STREAM_INPUT]); snd_rawmidi_free_substreams(&rmidi->streams[SNDRV_RAWMIDI_STREAM_OUTPUT]);