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=-18.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,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 19A3EC48BC2 for ; Wed, 23 Jun 2021 13:09:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EB5AA60FD8 for ; Wed, 23 Jun 2021 13:09:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230490AbhFWNLo (ORCPT ); Wed, 23 Jun 2021 09:11:44 -0400 Received: from smtp-out1.suse.de ([195.135.220.28]:51428 "EHLO smtp-out1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230496AbhFWNLk (ORCPT ); Wed, 23 Jun 2021 09:11:40 -0400 Received: from imap.suse.de (imap-alt.suse-dmz.suse.de [192.168.254.47]) (using TLSv1.2 with cipher ECDHE-ECDSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id 3764521962; Wed, 23 Jun 2021 13:09:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1624453760; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=fvLe4EDcZBFIJFV4utDnoKGG4SlCKvEBy8vMSAJDpnk=; b=JvFAJrnRk4z9JofF9qR8IZLIrtA/HR4LsTpSYytHLGr/baiqJyKWcoa8i77iQYjkHGDtPG nYCqIBCJPS3jLWcXfr2juHvEIVvlZd0a1X2+W61iXuQ1PV0TMhkYUzTbGzHjeNOQrJm9Ix TgdnlutnZLfBh6DyZ7HJqAeYOQKMUPk= Received: from imap3-int (imap-alt.suse-dmz.suse.de [192.168.254.47]) by imap.suse.de (Postfix) with ESMTP id F245A11A97; Wed, 23 Jun 2021 13:09:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1624453760; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=fvLe4EDcZBFIJFV4utDnoKGG4SlCKvEBy8vMSAJDpnk=; b=JvFAJrnRk4z9JofF9qR8IZLIrtA/HR4LsTpSYytHLGr/baiqJyKWcoa8i77iQYjkHGDtPG nYCqIBCJPS3jLWcXfr2juHvEIVvlZd0a1X2+W61iXuQ1PV0TMhkYUzTbGzHjeNOQrJm9Ix TgdnlutnZLfBh6DyZ7HJqAeYOQKMUPk= Received: from director2.suse.de ([192.168.254.72]) by imap3-int with ESMTPSA id ol9pOX8y02DIMQAALh3uQQ (envelope-from ); Wed, 23 Jun 2021 13:09:19 +0000 From: Juergen Gross To: xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org Cc: Juergen Gross , Boris Ostrovsky , Stefano Stabellini , Julien Grall Subject: [PATCH] xen/events: reset active flag for lateeoi events later Date: Wed, 23 Jun 2021 15:09:13 +0200 Message-Id: <20210623130913.9405-1-jgross@suse.com> X-Mailer: git-send-email 2.26.2 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In order to avoid a race condition for user events when changing cpu affinity reset the active flag only when EOI-ing the event. This is working fine as all user events are lateeoi events. Note that lateeoi_ack_mask_dynirq() is not modified as there is no explicit call to xen_irq_lateeoi() expected later. Reported-by: Julien Grall Fixes: b6622798bc50b62 ("xen/events: avoid handling the same event on two cpus at the same time") Tested-by: Julien Grall Signed-off-by: Juergen Gross --- drivers/xen/events/events_base.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/drivers/xen/events/events_base.c b/drivers/xen/events/events_base.c index 7bbfd58958bc..d7e361fb0548 100644 --- a/drivers/xen/events/events_base.c +++ b/drivers/xen/events/events_base.c @@ -642,6 +642,9 @@ static void xen_irq_lateeoi_locked(struct irq_info *info, bool spurious) } info->eoi_time = 0; + + /* is_active hasn't been reset yet, do it now. */ + smp_store_release(&info->is_active, 0); do_unmask(info, EVT_MASK_REASON_EOI_PENDING); } @@ -811,6 +814,7 @@ static void xen_evtchn_close(evtchn_port_t port) BUG(); } +/* Not called for lateeoi events. */ static void event_handler_exit(struct irq_info *info) { smp_store_release(&info->is_active, 0); @@ -1883,7 +1887,12 @@ static void lateeoi_ack_dynirq(struct irq_data *data) if (VALID_EVTCHN(evtchn)) { do_mask(info, EVT_MASK_REASON_EOI_PENDING); - event_handler_exit(info); + /* + * Don't call event_handler_exit(). + * Need to keep is_active non-zero in order to ignore re-raised + * events after cpu affinity changes while a lateeoi is pending. + */ + clear_evtchn(evtchn); } } -- 2.26.2