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 0C75EC25B0F for ; Sun, 14 Aug 2022 16:34:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242653AbiHNQe5 (ORCPT ); Sun, 14 Aug 2022 12:34:57 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51324 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242666AbiHNQdn (ORCPT ); Sun, 14 Aug 2022 12:33:43 -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 6F9202C118; Sun, 14 Aug 2022 09:27:25 -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 15981B80B37; Sun, 14 Aug 2022 16:27:24 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id ED974C433D7; Sun, 14 Aug 2022 16:27:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1660494442; bh=X/ZLYxxDnih0e0paGcYJ4tSJ7KVpOyF0ATP2RLTK/q4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=uh13lgItE4/WLXXSLr3LSEjHbRkjqhIdc2kdnhdKqwhxM3sFPh5IpZWqRvaRDn2Wh KE2wXUllzCp2vdnTsLkTJyt/NnzvM0kHopcs2Ruzq5W5lzIFDB72c4MYrFmhVWTDzD 4O80KDB8KXS/BlTJmsb9Rnw7PqlNRo6R8oCgHJyWH4pezLYIbNMA93Xi1Z8iHzdMxS 2hJe6xE4chMcpid7cwrcASgDOKQHkzInXn+TzFs4gtit90x1ECVk+qS1+Kjw/7XhLY UMjKSbC8FF0SvccndMf3wFHXEZm4XRbQqkZx972mXAwfiNP4KL5toOUBV3N6X0T5j1 zxI8rYZ/HSUzQ== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Takashi Iwai , Sasha Levin , perex@perex.cz, tiwai@suse.com, alsa-devel@alsa-project.org Subject: [PATCH AUTOSEL 5.15 21/28] ALSA: control: Use deferred fasync helper Date: Sun, 14 Aug 2022 12:26:01 -0400 Message-Id: <20220814162610.2397644-21-sashal@kernel.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220814162610.2397644-1-sashal@kernel.org> References: <20220814162610.2397644-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Takashi Iwai [ Upstream commit 4a971e84a7ae10a38d875cd2d4e487c8d1682ca3 ] For avoiding the potential deadlock via kill_fasync() call, use the new fasync helpers to defer the invocation from the control API. Note that it's merely a workaround. Another note: although we haven't received reports about the deadlock with the control API, the deadlock is still potentially possible, and it's better to align the behavior with other core APIs (PCM and timer); so let's move altogether. Link: https://lore.kernel.org/r/20220728125945.29533-5-tiwai@suse.de Signed-off-by: Takashi Iwai Signed-off-by: Sasha Levin --- include/sound/control.h | 2 +- sound/core/control.c | 7 ++++--- 2 files changed, 5 insertions(+), 4 deletions(-) diff --git a/include/sound/control.h b/include/sound/control.h index 985c51a8fb74..a1fc7e0a47d9 100644 --- a/include/sound/control.h +++ b/include/sound/control.h @@ -109,7 +109,7 @@ struct snd_ctl_file { int preferred_subdevice[SND_CTL_SUBDEV_ITEMS]; wait_queue_head_t change_sleep; spinlock_t read_lock; - struct fasync_struct *fasync; + struct snd_fasync *fasync; int subscribed; /* read interface is activated */ struct list_head events; /* waiting events for read */ }; diff --git a/sound/core/control.c b/sound/core/control.c index a25c0d64d104..f66fe4be30d3 100644 --- a/sound/core/control.c +++ b/sound/core/control.c @@ -127,6 +127,7 @@ static int snd_ctl_release(struct inode *inode, struct file *file) if (control->vd[idx].owner == ctl) control->vd[idx].owner = NULL; up_write(&card->controls_rwsem); + snd_fasync_free(ctl->fasync); snd_ctl_empty_read_queue(ctl); put_pid(ctl->pid); kfree(ctl); @@ -181,7 +182,7 @@ void snd_ctl_notify(struct snd_card *card, unsigned int mask, _found: wake_up(&ctl->change_sleep); spin_unlock(&ctl->read_lock); - kill_fasync(&ctl->fasync, SIGIO, POLL_IN); + snd_kill_fasync(ctl->fasync, SIGIO, POLL_IN); } read_unlock_irqrestore(&card->ctl_files_rwlock, flags); } @@ -2002,7 +2003,7 @@ static int snd_ctl_fasync(int fd, struct file * file, int on) struct snd_ctl_file *ctl; ctl = file->private_data; - return fasync_helper(fd, file, on, &ctl->fasync); + return snd_fasync_helper(fd, file, on, &ctl->fasync); } /* return the preferred subdevice number if already assigned; @@ -2170,7 +2171,7 @@ static int snd_ctl_dev_disconnect(struct snd_device *device) read_lock_irqsave(&card->ctl_files_rwlock, flags); list_for_each_entry(ctl, &card->ctl_files, list) { wake_up(&ctl->change_sleep); - kill_fasync(&ctl->fasync, SIGIO, POLL_ERR); + snd_kill_fasync(ctl->fasync, SIGIO, POLL_ERR); } read_unlock_irqrestore(&card->ctl_files_rwlock, flags); -- 2.35.1