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=-8.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED 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 2560AC3A5A1 for ; Thu, 22 Aug 2019 13:09:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id F305F21726 for ; Thu, 22 Aug 2019 13:09:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389003AbfHVNJU (ORCPT ); Thu, 22 Aug 2019 09:09:20 -0400 Received: from bilbo.ozlabs.org ([203.11.71.1]:53435 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388969AbfHVNJO (ORCPT ); Thu, 22 Aug 2019 09:09:14 -0400 Received: by ozlabs.org (Postfix, from userid 1034) id 46DlGv5YRdz9sPl; Thu, 22 Aug 2019 23:09:11 +1000 (AEST) X-powerpc-patch-notification: thanks X-powerpc-patch-commit: 415480dce2ef03bb8335deebd2f402f475443ce0 In-Reply-To: <80432f71194d7ee75b2f5043ecf1501cf1cca1f3.1566196646.git.christophe.leroy@c-s.fr> To: Christophe Leroy , Benjamin Herrenschmidt , Paul Mackerras , Doug Crawford From: Michael Ellerman Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] powerpc/603: fix handling of the DIRTY flag Message-Id: <46DlGv5YRdz9sPl@ozlabs.org> Date: Thu, 22 Aug 2019 23:09:11 +1000 (AEST) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2019-08-19 at 06:40:25 UTC, Christophe Leroy wrote: > If a page is already mapped RW without the DIRTY flag, the DIRTY > flag is never set and a TLB store miss exception is taken forever. > > This is easily reproduced with the following app: > > void main(void) > { > volatile char *ptr = mmap(0, 4096, PROT_READ | PROT_WRITE, MAP_SHARED | MAP_ANONYMOUS, -1, 0); > > *ptr = *ptr; > } > > When DIRTY flag is not set, bail out of TLB miss handler and take > a minor page fault which will set the DIRTY flag. > > Fixes: f8b58c64eaef ("powerpc/603: let's handle PAGE_DIRTY directly") > Cc: stable@vger.kernel.org > Reported-by: Doug Crawford > Signed-off-by: Christophe Leroy Applied to powerpc next, thanks. https://git.kernel.org/powerpc/c/415480dce2ef03bb8335deebd2f402f475443ce0 cheers