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=-8.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 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 8F84FC433E1 for ; Fri, 21 Aug 2020 18:45:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6F9F620735 for ; Fri, 21 Aug 2020 18:45:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726598AbgHUSpK (ORCPT ); Fri, 21 Aug 2020 14:45:10 -0400 Received: from l2mail1.panix.com ([166.84.1.75]:56142 "EHLO l2mail1.panix.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725906AbgHUSpJ (ORCPT ); Fri, 21 Aug 2020 14:45:09 -0400 X-Greylist: delayed 970 seconds by postgrey-1.27 at vger.kernel.org; Fri, 21 Aug 2020 14:45:09 EDT Received: from mailbackend.panix.com (mailbackend.panix.com [166.84.1.89]) by l2mail1.panix.com (Postfix) with ESMTPS id 4BY95W0HJszDdc; Fri, 21 Aug 2020 14:29:02 -0400 (EDT) Received: from xps-7390 (cpe-23-242-39-94.socal.res.rr.com [23.242.39.94]) by mailbackend.panix.com (Postfix) with ESMTPSA id 4BY95Q1Z1Lz1XCR; Fri, 21 Aug 2020 14:28:58 -0400 (EDT) Date: Fri, 21 Aug 2020 11:28:57 -0700 (PDT) From: "Kenneth R. Crudup" Reply-To: "Kenneth R. Crudup" To: "Rafael J. Wysocki" cc: Linux ACPI , LKML , Mika Westerberg , "Krogerus, Heikki" Subject: Re: [PATCH] ACPI: OSL: Prevent acpi_release_memory() from returning too early In-Reply-To: <6142241.0H6QnnlUA7@kreacher> Message-ID: References: <6142241.0H6QnnlUA7@kreacher> User-Agent: Alpine 2.23 (DEB 453 2020-06-18) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: linux-acpi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org Works here for me: ---- $ l /sys/class/typec total 0 10012 0 drwxr-xr-x 2 root root 0 Aug 21 11:25 ./ 10 0 drwxr-xr-x 67 root root 0 Aug 21 11:25 ../ 27771 0 lrwxrwxrwx 1 root root 0 Aug 21 11:25 port0 -> ../../devices/platform/USBC000:00/typec/port0/ 35601 0 lrwxrwxrwx 1 root root 0 Aug 21 11:25 port0-partner -> ../../devices/platform/USBC000:00/typec/port0/port0-partner/ 36686 0 lrwxrwxrwx 1 root root 0 Aug 21 11:25 port1 -> ../../devices/platform/USBC000:00/typec/port1/ $ ---- On Fri, 21 Aug 2020, Rafael J. Wysocki wrote: > From: Rafael J. Wysocki > > After commit 1757659d022b ("ACPI: OSL: Implement deferred unmapping > of ACPI memory") in some cases acpi_release_memory() may return > before the target memory mappings actually go away, because they > are released asynchronously now. > > Prevent it from returning prematurely by making it wait for the next > RCU grace period to elapse, for all of the RCU callbacks to complete > and for all of the scheduled work items to be flushed before > returning. > > Fixes: 1757659d022b ("ACPI: OSL: Implement deferred unmapping of ACPI memory") > Reported-by: Kenneth R. Crudup > Signed-off-by: Rafael J. Wysocki > --- > drivers/acpi/osl.c | 19 +++++++++++++++++-- > 1 file changed, 17 insertions(+), 2 deletions(-) > > Index: linux-pm/drivers/acpi/osl.c > =================================================================== > --- linux-pm.orig/drivers/acpi/osl.c > +++ linux-pm/drivers/acpi/osl.c > @@ -1575,11 +1575,26 @@ static acpi_status acpi_deactivate_mem_r > acpi_status acpi_release_memory(acpi_handle handle, struct resource *res, > u32 level) > { > + acpi_status status; > + > if (!(res->flags & IORESOURCE_MEM)) > return AE_TYPE; > > - return acpi_walk_namespace(ACPI_TYPE_REGION, handle, level, > - acpi_deactivate_mem_region, NULL, res, NULL); > + status = acpi_walk_namespace(ACPI_TYPE_REGION, handle, level, > + acpi_deactivate_mem_region, NULL, > + res, NULL); > + if (ACPI_FAILURE(status)) > + return status; > + > + /* > + * Wait for all of the mappings queued up for removal by > + * acpi_deactivate_mem_region() to actually go away. > + */ > + synchronize_rcu(); > + rcu_barrier(); > + flush_scheduled_work(); > + > + return AE_OK; > } > EXPORT_SYMBOL_GPL(acpi_release_memory); > > > > > -- Kenneth R. Crudup Sr. SW Engineer, Scott County Consulting, Orange County CA