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=-6.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED,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 C2447C10F11 for ; Wed, 24 Apr 2019 17:52:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8F87521773 for ; Wed, 24 Apr 2019 17:52:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1556128374; bh=yaNplxSsfZOo+8AP0DyS7wIs6YMZ8vEhqvqmfjteW5Q=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=q59oqih6ahyowuxb5rGMucVdAWZQCyK4qYHl1u78H3QRQOZVo3G044euNTLSL50Zt 9BLCdaT2SVqx1bPHvvW+lQ56/cD2C7HTYAXFmpW/453WL+uryvzQbx1zfMBf5aDaca 4tiX/bjmdY9Be3+ge71DIBer7RbH28uriw2P03FA= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388478AbfDXRwr (ORCPT ); Wed, 24 Apr 2019 13:52:47 -0400 Received: from mail.kernel.org ([198.145.29.99]:54002 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390546AbfDXR1x (ORCPT ); Wed, 24 Apr 2019 13:27:53 -0400 Received: from localhost (62-193-50-229.as16211.net [62.193.50.229]) (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 55F4721909; Wed, 24 Apr 2019 17:27:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1556126872; bh=yaNplxSsfZOo+8AP0DyS7wIs6YMZ8vEhqvqmfjteW5Q=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=yG/XLvITcTORS2HxERT6EwqQe82Qt/W8IavpGZQ9Bs1aVySMjniHR6tiy99r6di4l DBtCBdGKbO57xHgTa3EYflGD3JHHJKZHh8oQFJTD7tILlllTyyrF/nEJeUJMpdKB8F W+JFOT3SoAA6dezAvcjc86yUr3PL15ACOzzmNUWA= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Mikhail Gavrilov , Thomas Gleixner , Thomas Lendacky Subject: [PATCH 4.14 47/70] x86/speculation: Prevent deadlock on ssb_state::lock Date: Wed, 24 Apr 2019 19:10:07 +0200 Message-Id: <20190424170915.780052601@linuxfoundation.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190424170906.751869122@linuxfoundation.org> References: <20190424170906.751869122@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Thomas Gleixner commit 2f5fb19341883bb6e37da351bc3700489d8506a7 upstream. Mikhail reported a lockdep splat related to the AMD specific ssb_state lock: CPU0 CPU1 lock(&st->lock); local_irq_disable(); lock(&(&sighand->siglock)->rlock); lock(&st->lock); lock(&(&sighand->siglock)->rlock); *** DEADLOCK *** The connection between sighand->siglock and st->lock comes through seccomp, which takes st->lock while holding sighand->siglock. Make sure interrupts are disabled when __speculation_ctrl_update() is invoked via prctl() -> speculation_ctrl_update(). Add a lockdep assert to catch future offenders. Fixes: 1f50ddb4f418 ("x86/speculation: Handle HT correctly on AMD") Reported-by: Mikhail Gavrilov Signed-off-by: Thomas Gleixner Tested-by: Mikhail Gavrilov Cc: Thomas Lendacky Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/alpine.DEB.2.21.1904141948200.4917@nanos.tec.linutronix.de Signed-off-by: Greg Kroah-Hartman --- arch/x86/kernel/process.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) --- a/arch/x86/kernel/process.c +++ b/arch/x86/kernel/process.c @@ -465,10 +467,12 @@ static unsigned long speculation_ctrl_up void speculation_ctrl_update(unsigned long tif) { + unsigned long flags; + /* Forced update. Make sure all relevant TIF flags are different */ - preempt_disable(); + local_irq_save(flags); __speculation_ctrl_update(~tif, tif); - preempt_enable(); + local_irq_restore(flags); } /* Called from seccomp/prctl update */