From patchwork Thu Feb 27 13:37:44 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 230283 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 F1045C52D4C for ; Thu, 27 Feb 2020 14:29:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BE62F24688 for ; Thu, 27 Feb 2020 14:29:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1582813773; bh=PiciUWh6trivm2waRdUpYO3vt8+/QQj86XcJO2eDsJc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=Be0jetpnWwEkuK3cCzaFU4ymHD6y2Cj74t7rLEw1Kk5cM1cTL8rGUVfUCoyJtYamp UHPDkag8hcV4IWZEOkKJll3mkXNC1uwBA9PjuEtaEfU86aFE0jyMzJsEKtiX20yNh1 pR5GruGKlhemXydQt3L+dnczTeo72eB2RN09EzY0= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387584AbgB0O3a (ORCPT ); Thu, 27 Feb 2020 09:29:30 -0500 Received: from mail.kernel.org ([198.145.29.99]:43764 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387948AbgB0OGc (ORCPT ); Thu, 27 Feb 2020 09:06:32 -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 3C07C21D7E; Thu, 27 Feb 2020 14:06:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1582812391; bh=PiciUWh6trivm2waRdUpYO3vt8+/QQj86XcJO2eDsJc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=cxXp3AGP3wt7klrNvloidVfkrFhSpDU9i3P9loVzm5t0S/TLVjI6Hr1pLgsm802FS URUt8wdH7iixJBgwp8GJXLHnEO/AmkwhPFCPOZtFYKQTQjH6eK9L8sq4et8WyP87wB ftG+7XlPZMvw91tHUeRqPU3D4TykNdDm586OzKIU= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Thomas Gleixner , Juergen Gross , Boris Ostrovsky Subject: [PATCH 4.19 96/97] xen: Enable interrupts when calling _cond_resched() Date: Thu, 27 Feb 2020 14:37:44 +0100 Message-Id: <20200227132230.358208395@linuxfoundation.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200227132214.553656188@linuxfoundation.org> References: <20200227132214.553656188@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: Thomas Gleixner commit 8645e56a4ad6dcbf504872db7f14a2f67db88ef2 upstream. xen_maybe_preempt_hcall() is called from the exception entry point xen_do_hypervisor_callback with interrupts disabled. _cond_resched() evades the might_sleep() check in cond_resched() which would have caught that and schedule_debug() unfortunately lacks a check for irqs_disabled(). Enable interrupts around the call and use cond_resched() to catch future issues. Fixes: fdfd811ddde3 ("x86/xen: allow privcmd hypercalls to be preempted") Signed-off-by: Thomas Gleixner Link: https://lore.kernel.org/r/878skypjrh.fsf@nanos.tec.linutronix.de Reviewed-by: Juergen Gross Signed-off-by: Boris Ostrovsky Signed-off-by: Greg Kroah-Hartman --- drivers/xen/preempt.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) --- a/drivers/xen/preempt.c +++ b/drivers/xen/preempt.c @@ -37,7 +37,9 @@ asmlinkage __visible void xen_maybe_pree * cpu. */ __this_cpu_write(xen_in_preemptible_hcall, false); - _cond_resched(); + local_irq_enable(); + cond_resched(); + local_irq_disable(); __this_cpu_write(xen_in_preemptible_hcall, true); } }