From patchwork Wed May 17 13:34:08 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ming Lei X-Patchwork-Id: 13245040 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9B832C77B75 for ; Wed, 17 May 2023 13:36:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231582AbjEQNgE (ORCPT ); Wed, 17 May 2023 09:36:04 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45194 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231408AbjEQNgD (ORCPT ); Wed, 17 May 2023 09:36:03 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9F41476AC for ; Wed, 17 May 2023 06:34:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1684330464; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=CbtW5Jmmv8Jo8I0xBOm+uh+DaT37Ll16E7lpSUKbIP8=; b=KtnOHYiKGJ99GbWBRX1HP6qO8OcIEuJhjTzpjc9iIh1ghksBNC0sGGGoiAPuAuAOKAUXdW YIUJGe5ODoDUzX1Su1cP9yYdCmCv2LlRICR4rFagIC6UKThE2d9cCaJ+ggd20D7+mXN9bo Ik1tToJu9t9QXfGma2vTiKsieJXR2rI= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-586-CmwUPwyINjKKhcOT1ijZuQ-1; Wed, 17 May 2023 09:34:20 -0400 X-MC-Unique: CmwUPwyINjKKhcOT1ijZuQ-1 Received: from smtp.corp.redhat.com (int-mx09.intmail.prod.int.rdu2.redhat.com [10.11.54.9]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id D6ADA3C10EC0; Wed, 17 May 2023 13:34:19 +0000 (UTC) Received: from localhost (ovpn-8-17.pek2.redhat.com [10.72.8.17]) by smtp.corp.redhat.com (Postfix) with ESMTP id B9DB9492B00; Wed, 17 May 2023 13:34:18 +0000 (UTC) From: Ming Lei To: Jens Axboe Cc: linux-block@vger.kernel.org, Ming Lei , Shinichiro Kawasaki , Ziyang Zhang Subject: [PATCH] ublk: fix AB-BA lockdep warning Date: Wed, 17 May 2023 21:34:08 +0800 Message-Id: <20230517133408.210944-1-ming.lei@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.9 Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org When handling UBLK_IO_FETCH_REQ, ctx->uring_lock is grabbed first, then ub->mutex is acquired. When handling UBLK_CMD_STOP_DEV or UBLK_CMD_DEL_DEV, ub->mutex is grabbed first, then calling io_uring_cmd_done() for canceling uring command, in which ctx->uring_lock may be required. Real deadlock only happens when all the above commands are issued from same uring context, and in reality different uring contexts are often used for handing control command and IO command. Fix the issue by using io_uring_cmd_complete_in_task() to cancel command in ublk_cancel_dev(ublk_cancel_queue). Reported-by: Shinichiro Kawasaki Closes: https://lore.kernel.org/linux-block/becol2g7sawl4rsjq2dztsbc7mqypfqko6wzsyoyazqydoasml@rcxarzwidrhk Cc: Ziyang Zhang Signed-off-by: Ming Lei Tested-by: Shinichiro Kawasaki --- drivers/block/ublk_drv.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c index c7ed5d69e9ee..33d3298a0da1 100644 --- a/drivers/block/ublk_drv.c +++ b/drivers/block/ublk_drv.c @@ -1120,6 +1120,11 @@ static inline bool ublk_queue_ready(struct ublk_queue *ubq) return ubq->nr_io_ready == ubq->q_depth; } +static void ublk_cmd_cancel_cb(struct io_uring_cmd *cmd, unsigned issue_flags) +{ + io_uring_cmd_done(cmd, UBLK_IO_RES_ABORT, 0, issue_flags); +} + static void ublk_cancel_queue(struct ublk_queue *ubq) { int i; @@ -1131,8 +1136,8 @@ static void ublk_cancel_queue(struct ublk_queue *ubq) struct ublk_io *io = &ubq->ios[i]; if (io->flags & UBLK_IO_FLAG_ACTIVE) - io_uring_cmd_done(io->cmd, UBLK_IO_RES_ABORT, 0, - IO_URING_F_UNLOCKED); + io_uring_cmd_complete_in_task(io->cmd, + ublk_cmd_cancel_cb); } /* all io commands are canceled */