From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757050Ab1KVCqZ (ORCPT ); Mon, 21 Nov 2011 21:46:25 -0500 Received: from mx1.redhat.com ([209.132.183.28]:45201 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753497Ab1KVCqY (ORCPT ); Mon, 21 Nov 2011 21:46:24 -0500 Message-ID: <4ECB0D7C.1020700@redhat.com> Date: Tue, 22 Nov 2011 10:48:28 +0800 From: Dave Young User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.15) Gecko/20110323 Thunderbird/3.1.9 MIME-Version: 1.0 To: Tejun Heo CC: WANG Cong , kexec@lists.infradead.org, tim@edgecast.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH] percpu: fix chunk range calculation References: <1321467647.2137.4.camel@boudreau> <4EC47FCA.5090908@redhat.com> <4EC491B3.705@redhat.com> <4EC4B60C.3030706@redhat.com> <1321548033.12208.12.camel@boudreau> <4EC61AB6.4090808@redhat.com> <4EC61B2A.7010000@redhat.com> <20111118185535.GA27152@google.com> <20111121211050.GK25776@google.com> In-Reply-To: <20111121211050.GK25776@google.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/22/2011 05:10 AM, Tejun Heo wrote: > On Fri, Nov 18, 2011 at 10:55:35AM -0800, Tejun Heo wrote: >> Percpu allocator recorded the cpus which map to the first and last >> units in pcpu_first/last_unit_cpu respectively and used them to >> determine the address range of a chunk - e.g. it assumed that the >> first unit has the lowest address in a chunk while the last unit has >> the highest address. >> >> This simply isn't true. Groups in a chunk can have arbitrary positive >> or negative offsets from the previous one and there is no guarantee >> that the first unit occupies the lowest offset while the last one the >> highest. >> >> Fix it by actually comparing unit offsets to determine cpus occupying >> the lowest and highest offsets. Also, rename pcu_first/last_unit_cpu >> to pcpu_low/high_unit_cpu to avoid confusion. >> >> The chunk address range is used to flush cache on vmalloc area >> map/unmap and decide whether a given address is in the first chunk by >> per_cpu_ptr_to_phys() and the bug was discovered by invalid >> per_cpu_ptr_to_phys() translation for crash_note. >> >> Kudos to Dave Young for tracking down the problem. >> >> Signed-off-by: Tejun Heo >> Reported-by: WANG Cong >> Reported-by: Dave Young >> LKML-Reference: <4EC21F67.10905@redhat.com> >> Cc: stable @kernel.org > > BTW, waiting for Tested-by. If someone gives me that, I'll push it > through percpu/for-fixes. Tested-by: Dave Young > > Thanks. > -- Thanks Dave