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=-0.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no 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 025AAC76188 for ; Sat, 20 Jul 2019 09:45:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D99662084D for ; Sat, 20 Jul 2019 09:45:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727584AbfGTJpn (ORCPT ); Sat, 20 Jul 2019 05:45:43 -0400 Received: from mx2.suse.de ([195.135.220.15]:43098 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727523AbfGTJpm (ORCPT ); Sat, 20 Jul 2019 05:45:42 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 587A3B11A; Sat, 20 Jul 2019 09:45:41 +0000 (UTC) From: Luis Henriques To: "Linus Torvalds" Cc: "Waiman Long" , "Borislav Petkov" , "Will Deacon" , "huang ying" , "Peter Zijlstra" , "the arch\/x86 maintainers" , "Thomas Gleixner" , "Tim Chen" , "Ingo Molnar" , "Davidlohr Bueso" , "Linux List Kernel Mailing" , "H. Peter Anvin" , "Jeff Layton" Subject: Re: [PATCH v8 13/19] locking/rwsem: Make rwsem->owner an atomic_long_t References: <20190520205918.22251-1-longman@redhat.com> <20190520205918.22251-14-longman@redhat.com> <20190719184538.GA20324@hermes.olymp> <2ed44afa-4528-a785-f188-2daf24343f97@redhat.com> <87h87hksim.fsf@suse.com> <87a7d9kq4a.fsf@suse.com> Date: Sat, 20 Jul 2019 10:45:39 +0100 In-Reply-To: <87a7d9kq4a.fsf@suse.com> (Luis Henriques's message of "Sat, 20 Jul 2019 10:32:53 +0100") Message-ID: <875znxkpj0.fsf@suse.com> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Luis Henriques writes: > Luis Henriques writes: > >> "Linus Torvalds" writes: >> >>> On Fri, Jul 19, 2019 at 12:32 PM Waiman Long wrote: >>>> >>>> This patch shouldn't change the behavior of the rwsem code. The code >>>> only access data within the rw_semaphore structures. I don't know why it >>>> will cause a KASAN error. I will have to reproduce it and figure out >>>> exactly which statement is doing the invalid access. >>> >>> The stack traces should show line numbers if you run them through >>> scripts/decode_stacktrace.sh. >>> >>> You need to have debug info enabled for that, though. >>> >>> Luis? >>> >>> Linus >> >> Yep, sure. And I should have done this in the initial report. It's a >> different trace, I had to recompile the kernel. >> >> (I'm also adding Jeff to the CC list.) >> > > Ah, and I also managed to reproduce this on btrfs so I guess this rules > out a bug in the filesystem code. Just another detail (before I go completely offline until tomorrow evening): in the btrfs case I'm seeing the bug on the rwsem_down_read_slowpath path, not on rwsem_down_write_slowpath. But it seems to be on the same place (i.e. rwsem_can_spin_on_owner). Cheers, -- Luis