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=-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=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 3CA57C52D2D for ; Thu, 27 Feb 2020 14:02:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0862324656 for ; Thu, 27 Feb 2020 14:02:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1582812158; bh=PiciUWh6trivm2waRdUpYO3vt8+/QQj86XcJO2eDsJc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=wW1BOpf73tmAdgV/WBZR8TNPRQfjtAshVYk3/8puzecrk9rRmc57xbg+WZAZUeWpu U5RgxR9sSsTEE0zp5k10DttYR9XWTc7mu2O5dtO/7xepVrqg+X3QPlkvIUhu7y+wXP jmrfvp7ElSiN9jRwzi3D7PB7Yr5edGHpwOoxqTLQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732881AbgB0OCh (ORCPT ); Thu, 27 Feb 2020 09:02:37 -0500 Received: from mail.kernel.org ([198.145.29.99]:37292 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1733149AbgB0OCe (ORCPT ); Thu, 27 Feb 2020 09:02:34 -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 918F82469B; Thu, 27 Feb 2020 14:02:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1582812154; bh=PiciUWh6trivm2waRdUpYO3vt8+/QQj86XcJO2eDsJc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=hyPqyM3U6r2jwnbaWLwqSVHvm0HOxiGE0j/RCIP7PtMnuy80lTM2pY3PNTyd54S8Y dOyMNJaopb0T6RjZTi4mfqM9eQfGyk7mlBrRs+s24YvrZRT+jtGF+0bHmyHrmXRzks jiwhhCHQ/3VzZEH98gfeANGSKagm111pUyyWF4Bo= 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 4.14 236/237] xen: Enable interrupts when calling _cond_resched() Date: Thu, 27 Feb 2020 14:37:30 +0100 Message-Id: <20200227132313.432076948@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 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@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); } }