Received: by 2002:a05:6a10:9848:0:0:0:0 with SMTP id x8csp3526256pxf; Mon, 15 Mar 2021 11:31:04 -0700 (PDT) X-Google-Smtp-Source: ABdhPJyG7S3kRvHWTO1eSdV1CficHq20YKYp3B3QV/6ZgZtUCK3/N96X5gcsxQD1M2ambQV9kNhg X-Received: by 2002:a17:906:400b:: with SMTP id v11mr25073860ejj.194.1615833064635; Mon, 15 Mar 2021 11:31:04 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1615833064; cv=none; d=google.com; s=arc-20160816; b=J6Tnyx0VqX+a+ak0ZjVVrX0UjF5D5TMw2pfjLsEXksFyGFlk5Ecf++04WL8fviOs4z Nx6atAW3XRhRlV0QjfuXkyYG+ArGbk3ZsW889D1IyjpYZunmlVmcy8QxPmeufN4DNxup kCbyL3rDUK7FZxzAIzY0RISerTHtbJCNKl9yzIeSv02qVLUYIF5LaN7pkS0yT8Rjh9P5 REIIei9ln0pkEev7RLqVkl0gSvXDhkiMY23ZGJi1KTq38pD8IA+aaLKqRHnz3QBbEZS0 /+rNy1gjUhxJN/l3nyEc7HYJkWklPLwbR+3C62yPBy1xPvFoOCuJWCulLae0b7jTlxqm GwkQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:content-transfer-encoding:mime-version :user-agent:references:in-reply-to:message-id:date:subject:cc:to :from:dkim-signature; bh=REsCMLlgMXo8RkNbCo3CjI3VXh6Ih8n/lbW+xK59b1U=; b=vOz8NsuElyQ199yWF9cg7W+io0io+M9php+xFRxoZvsmWrHzKr8DrzuJJ6Ya9Z5eOz aMNDe1S2N0/7QFd/HPsBGmxxtKDdy2A7uY3PiXV8pxBzKjzvKNQTF2VN4/z2ty1p9RbL gp0jqRNBqrK7XR1I4f6/pr4N4NGeH1Dt43iXCA8VSbF5XT2saS6iYmzfnihZaPl5iBC/ 1uXMhq4lqgxIKca4IsTOHa7pxUBoAV0+TlpL1YMiKuEVjtLm6rsHoKNLQzBARnK30GYk B7U8P6wDQWqoXijWE3qHiwPobsbBzcZwpDM/CcbxUUwdwUc4XR6UMUishFTnDIQPQzFL V8/g== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@linuxfoundation.org header.s=korg header.b=uxicCdzb; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=linuxfoundation.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [23.128.96.18]) by mx.google.com with ESMTP id z2si2116945eju.371.2021.03.15.11.30.42; Mon, 15 Mar 2021 11:31:04 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; dkim=pass header.i=@linuxfoundation.org header.s=korg header.b=uxicCdzb; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=linuxfoundation.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236482AbhCOOgn (ORCPT + 99 others); Mon, 15 Mar 2021 10:36:43 -0400 Received: from mail.kernel.org ([198.145.29.99]:37476 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233393AbhCOOBi (ORCPT ); Mon, 15 Mar 2021 10:01:38 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 570C864FC3; Mon, 15 Mar 2021 14:01:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1615816869; bh=HxQmE0RP0LzC8UMxFs5pgAUqlRaAFNSF8+QAirZSGeo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=uxicCdzbK2T0jFAMeo83TD0SDvaeMzEHRZcMeDgay8Fc0PwfhD9DNQa+3Kz2zCCcp jJ4mHUo8Z1LnRJSJvBxHYt7StHQsOUvZG6tPi66H5GCgBy0EZxjiMt65QjqSmMk0Gd 85VilHlcuKlay5Bub/eTXfZV9EDIlmbfJXxw0aEU= From: gregkh@linuxfoundation.org To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Julien Grall , Juergen Gross , Julien Grall , Boris Ostrovsky Subject: [PATCH 4.19 120/120] xen/events: avoid handling the same event on two cpus at the same time Date: Mon, 15 Mar 2021 14:57:51 +0100 Message-Id: <20210315135723.907145438@linuxfoundation.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210315135720.002213995@linuxfoundation.org> References: <20210315135720.002213995@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Greg Kroah-Hartman From: Juergen Gross commit b6622798bc50b625a1e62f82c7190df40c1f5b21 upstream. When changing the cpu affinity of an event it can happen today that (with some unlucky timing) the same event will be handled on the old and the new cpu at the same time. Avoid that by adding an "event active" flag to the per-event data and call the handler only if this flag isn't set. Cc: stable@vger.kernel.org Reported-by: Julien Grall Signed-off-by: Juergen Gross Reviewed-by: Julien Grall Link: https://lore.kernel.org/r/20210306161833.4552-4-jgross@suse.com Signed-off-by: Boris Ostrovsky Signed-off-by: Greg Kroah-Hartman --- drivers/xen/events/events_base.c | 25 +++++++++++++++++-------- drivers/xen/events/events_internal.h | 1 + 2 files changed, 18 insertions(+), 8 deletions(-) --- a/drivers/xen/events/events_base.c +++ b/drivers/xen/events/events_base.c @@ -693,6 +693,12 @@ static void xen_evtchn_close(unsigned in BUG(); } +static void event_handler_exit(struct irq_info *info) +{ + smp_store_release(&info->is_active, 0); + clear_evtchn(info->evtchn); +} + static void pirq_query_unmask(int irq) { struct physdev_irq_status_query irq_status; @@ -723,13 +729,13 @@ static void eoi_pirq(struct irq_data *da likely(!irqd_irq_disabled(data))) { do_mask(info, EVT_MASK_REASON_TEMPORARY); - clear_evtchn(evtchn); + event_handler_exit(info); irq_move_masked_irq(data); do_unmask(info, EVT_MASK_REASON_TEMPORARY); } else - clear_evtchn(evtchn); + event_handler_exit(info); if (pirq_needs_eoi(data->irq)) { rc = HYPERVISOR_physdev_op(PHYSDEVOP_eoi, &eoi); @@ -1565,6 +1571,8 @@ void handle_irq_for_port(evtchn_port_t p } info = info_for_irq(irq); + if (xchg_acquire(&info->is_active, 1)) + return; if (ctrl->defer_eoi) { info->eoi_cpu = smp_processor_id(); @@ -1752,13 +1760,13 @@ static void ack_dynirq(struct irq_data * likely(!irqd_irq_disabled(data))) { do_mask(info, EVT_MASK_REASON_TEMPORARY); - clear_evtchn(evtchn); + event_handler_exit(info); irq_move_masked_irq(data); do_unmask(info, EVT_MASK_REASON_TEMPORARY); } else - clear_evtchn(evtchn); + event_handler_exit(info); } static void mask_ack_dynirq(struct irq_data *data) @@ -1774,7 +1782,7 @@ static void lateeoi_ack_dynirq(struct ir if (VALID_EVTCHN(evtchn)) { do_mask(info, EVT_MASK_REASON_EOI_PENDING); - clear_evtchn(evtchn); + event_handler_exit(info); } } @@ -1785,7 +1793,7 @@ static void lateeoi_mask_ack_dynirq(stru if (VALID_EVTCHN(evtchn)) { do_mask(info, EVT_MASK_REASON_EXPLICIT); - clear_evtchn(evtchn); + event_handler_exit(info); } } @@ -1894,10 +1902,11 @@ static void restore_cpu_ipis(unsigned in /* Clear an irq's pending state, in preparation for polling on it */ void xen_clear_irq_pending(int irq) { - int evtchn = evtchn_from_irq(irq); + struct irq_info *info = info_for_irq(irq); + evtchn_port_t evtchn = info ? info->evtchn : 0; if (VALID_EVTCHN(evtchn)) - clear_evtchn(evtchn); + event_handler_exit(info); } EXPORT_SYMBOL(xen_clear_irq_pending); void xen_set_irq_pending(int irq) --- a/drivers/xen/events/events_internal.h +++ b/drivers/xen/events/events_internal.h @@ -40,6 +40,7 @@ struct irq_info { #define EVT_MASK_REASON_EXPLICIT 0x01 #define EVT_MASK_REASON_TEMPORARY 0x02 #define EVT_MASK_REASON_EOI_PENDING 0x04 + u8 is_active; /* Is event just being handled? */ unsigned irq; unsigned int evtchn; /* event channel */ unsigned short cpu; /* cpu bound */