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=-3.7 required=3.0 tests=BAYES_00, 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 2E1DFC433DF for ; Sat, 17 Oct 2020 11:13:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DFFB2206D4 for ; Sat, 17 Oct 2020 11:13:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2437356AbgJQLNe (ORCPT ); Sat, 17 Oct 2020 07:13:34 -0400 Received: from smtp1.kaist.ac.kr ([143.248.5.228]:53263 "EHLO smtp1.kaist.ac.kr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2437174AbgJQLNe (ORCPT ); Sat, 17 Oct 2020 07:13:34 -0400 X-Greylist: delayed 394 seconds by postgrey-1.27 at vger.kernel.org; Sat, 17 Oct 2020 07:13:33 EDT Received: from unknown (HELO mail1.kaist.ac.kr) (143.248.5.247) by 143.248.5.228 with ESMTP; 17 Oct 2020 20:06:50 +0900 X-Original-SENDERIP: 143.248.5.247 X-Original-MAILFROM: dae.r.jeong@kaist.ac.kr X-Original-RCPTTO: linux-kernel@vger.kernel.org Received: from kaist.ac.kr (143.248.133.220) by kaist.ac.kr with ESMTP imoxion SensMail SmtpServer 7.0 id <595760cb0b67440a9c04038fe1fdce40> from ; Sat, 17 Oct 2020 20:06:51 +0900 Date: Sat, 17 Oct 2020 20:06:51 +0900 From: "Dae R. Jeong" To: song@kernel.org Cc: yjkwon@kaist.ac.kr, linux-raid@vger.kernel.org, linux-kernel@vger.kernel.org Subject: WARNING in md_ioctl Message-ID: <20201017110651.GA1602260@dragonet> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, I looked into the warning "WARNING in md_ioctl" found by Syzkaller. (https://syzkaller.appspot.com/bug?id=fbf9eaea2e65bfcabb4e2750c3ab0892867edea1) I suspect that it is caused by a race between two concurrenct ioctl()s as belows. CPU1 (md_ioctl()) CPU2 (md_ioctl()) ------ ------ set_bit(MD_CLOSING, &mddev->flags); did_set_md_closing = true; WARN_ON_ONCE(test_bit(MD_CLOSING, &mddev->flags)); if(did_set_md_closing) clear_bit(MD_CLOSING, &mddev->flags); If the above is correct, this warning is introduced in the commit 065e519e("md: MD_CLOSING needs to be cleared after called md_set_readonly or do_md_stop"). Could you please take a look into this? Best regards, Dae R. Jeong