From patchwork Thu Feb 27 13:37:27 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 230257 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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable 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 C93CDC5ED25 for ; Thu, 27 Feb 2020 14:32:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A201624656 for ; Thu, 27 Feb 2020 14:32:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1582813946; bh=lot9hp8M9ZmQ4SErYioRkTfv2/FgtyO+wcAr43RWXLg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=oEDKSoqbQxGvlhBCnLDCdXWpKqq6MbVsY1XglIQD3bVaPinGndJED1UbU8y76Ptw7 OfTv0p8Eyqb6zckbTa/sbGBIaS0vto43FQ/JkidsjEmySJ1JSXE2tGjmsfzGQUgktm 7wQ8MI8TWRdfE1IsAw/FFWg5IbeWG/CYuBBpDTG8= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729894AbgB0OCP (ORCPT ); Thu, 27 Feb 2020 09:02:15 -0500 Received: from mail.kernel.org ([198.145.29.99]:36798 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732644AbgB0OCO (ORCPT ); Thu, 27 Feb 2020 09:02:14 -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 2F30324697; Thu, 27 Feb 2020 14:02:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1582812133; bh=lot9hp8M9ZmQ4SErYioRkTfv2/FgtyO+wcAr43RWXLg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=nm3L0AUkvS4Pz2gaWoEbgRMn0Ds4VBrkDb5dB7lsEEPePchNqt/TbybYPg/4Wc/1y Qo53W1NoWIGcw92T19MDb8m2zCfeJ32jj8Za3TZb03+NQpif6i2mPxM8bIurMUHxyO Wt+dI6XYflOBwLLAzML9mPWAt6q3D1DbDOkId98Y= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, syzbot+fd5e0eaa1a32999173b2@syzkaller.appspotmail.com, Takashi Iwai Subject: [PATCH 4.14 233/237] ALSA: seq: Fix concurrent access to queue current tick/time Date: Thu, 27 Feb 2020 14:37:27 +0100 Message-Id: <20200227132313.225759903@linuxfoundation.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200227132255.285644406@linuxfoundation.org> References: <20200227132255.285644406@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Takashi Iwai commit dc7497795e014d84699c3b8809ed6df35352dd74 upstream. snd_seq_check_queue() passes the current tick and time of the given queue as a pointer to snd_seq_prioq_cell_out(), but those might be updated concurrently by the seq timer update. Fix it by retrieving the current tick and time via the proper helper functions at first, and pass those values to snd_seq_prioq_cell_out() later in the loops. snd_seq_timer_get_cur_time() takes a new argument and adjusts with the current system time only when it's requested so; this update isn't needed for snd_seq_check_queue(), as it's called either from the interrupt handler or right after queuing. Also, snd_seq_timer_get_cur_tick() is changed to read the value in the spinlock for the concurrency, too. Reported-by: syzbot+fd5e0eaa1a32999173b2@syzkaller.appspotmail.com Link: https://lore.kernel.org/r/20200214111316.26939-3-tiwai@suse.de Signed-off-by: Takashi Iwai Signed-off-by: Greg Kroah-Hartman --- sound/core/seq/seq_clientmgr.c | 4 ++-- sound/core/seq/seq_queue.c | 9 ++++++--- sound/core/seq/seq_timer.c | 13 ++++++++++--- sound/core/seq/seq_timer.h | 3 ++- 4 files changed, 20 insertions(+), 9 deletions(-) --- a/sound/core/seq/seq_clientmgr.c +++ b/sound/core/seq/seq_clientmgr.c @@ -564,7 +564,7 @@ static int update_timestamp_of_queue(str event->queue = queue; event->flags &= ~SNDRV_SEQ_TIME_STAMP_MASK; if (real_time) { - event->time.time = snd_seq_timer_get_cur_time(q->timer); + event->time.time = snd_seq_timer_get_cur_time(q->timer, true); event->flags |= SNDRV_SEQ_TIME_STAMP_REAL; } else { event->time.tick = snd_seq_timer_get_cur_tick(q->timer); @@ -1639,7 +1639,7 @@ static int snd_seq_ioctl_get_queue_statu tmr = queue->timer; status->events = queue->tickq->cells + queue->timeq->cells; - status->time = snd_seq_timer_get_cur_time(tmr); + status->time = snd_seq_timer_get_cur_time(tmr, true); status->tick = snd_seq_timer_get_cur_tick(tmr); status->running = tmr->running; --- a/sound/core/seq/seq_queue.c +++ b/sound/core/seq/seq_queue.c @@ -261,6 +261,8 @@ void snd_seq_check_queue(struct snd_seq_ { unsigned long flags; struct snd_seq_event_cell *cell; + snd_seq_tick_time_t cur_tick; + snd_seq_real_time_t cur_time; if (q == NULL) return; @@ -277,17 +279,18 @@ void snd_seq_check_queue(struct snd_seq_ __again: /* Process tick queue... */ + cur_tick = snd_seq_timer_get_cur_tick(q->timer); for (;;) { - cell = snd_seq_prioq_cell_out(q->tickq, - &q->timer->tick.cur_tick); + cell = snd_seq_prioq_cell_out(q->tickq, &cur_tick); if (!cell) break; snd_seq_dispatch_event(cell, atomic, hop); } /* Process time queue... */ + cur_time = snd_seq_timer_get_cur_time(q->timer, false); for (;;) { - cell = snd_seq_prioq_cell_out(q->timeq, &q->timer->cur_time); + cell = snd_seq_prioq_cell_out(q->timeq, &cur_time); if (!cell) break; snd_seq_dispatch_event(cell, atomic, hop); --- a/sound/core/seq/seq_timer.c +++ b/sound/core/seq/seq_timer.c @@ -436,14 +436,15 @@ int snd_seq_timer_continue(struct snd_se } /* return current 'real' time. use timeofday() to get better granularity. */ -snd_seq_real_time_t snd_seq_timer_get_cur_time(struct snd_seq_timer *tmr) +snd_seq_real_time_t snd_seq_timer_get_cur_time(struct snd_seq_timer *tmr, + bool adjust_ktime) { snd_seq_real_time_t cur_time; unsigned long flags; spin_lock_irqsave(&tmr->lock, flags); cur_time = tmr->cur_time; - if (tmr->running) { + if (adjust_ktime && tmr->running) { struct timespec64 tm; ktime_get_ts64(&tm); @@ -460,7 +461,13 @@ snd_seq_real_time_t snd_seq_timer_get_cu high PPQ values) */ snd_seq_tick_time_t snd_seq_timer_get_cur_tick(struct snd_seq_timer *tmr) { - return tmr->tick.cur_tick; + snd_seq_tick_time_t cur_tick; + unsigned long flags; + + spin_lock_irqsave(&tmr->lock, flags); + cur_tick = tmr->tick.cur_tick; + spin_unlock_irqrestore(&tmr->lock, flags); + return cur_tick; } --- a/sound/core/seq/seq_timer.h +++ b/sound/core/seq/seq_timer.h @@ -135,7 +135,8 @@ int snd_seq_timer_set_ppq(struct snd_seq int snd_seq_timer_set_position_tick(struct snd_seq_timer *tmr, snd_seq_tick_time_t position); int snd_seq_timer_set_position_time(struct snd_seq_timer *tmr, snd_seq_real_time_t position); int snd_seq_timer_set_skew(struct snd_seq_timer *tmr, unsigned int skew, unsigned int base); -snd_seq_real_time_t snd_seq_timer_get_cur_time(struct snd_seq_timer *tmr); +snd_seq_real_time_t snd_seq_timer_get_cur_time(struct snd_seq_timer *tmr, + bool adjust_ktime); snd_seq_tick_time_t snd_seq_timer_get_cur_tick(struct snd_seq_timer *tmr); extern int seq_default_timer_class;