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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2883EE95A8E for ; Mon, 9 Oct 2023 13:34:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1377145AbjJINe2 (ORCPT ); Mon, 9 Oct 2023 09:34:28 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49322 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1377146AbjJINe1 (ORCPT ); Mon, 9 Oct 2023 09:34:27 -0400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6924594 for ; Mon, 9 Oct 2023 06:34:25 -0700 (PDT) Received: by smtp.kernel.org (Postfix) with ESMTPSA id AD25DC433C7; Mon, 9 Oct 2023 13:34:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1696858465; bh=RtbrMGkIgsVOGsTrpPZ3QyoxvdDNF6ZeeGZ+M0QS5PY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Y8ff15DiDAvQhiTVL66mOJHSD9VqfOB6ROMNl/GOnwpLrUasSIi1L/5gYKKlq1Tr/ A3oUUKoFbU7xm+jlWDefUnrRJiR8YUnau1z+B1mblYM24z9B7hi8foNOhIJQWDlCOC M2TlLiF8G3Xonymt8cvGS/+Q+1QERJxtjlw6dKNY= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Junxiao Bi , Mike Christie , "Martin K. Petersen" , Sasha Levin Subject: [PATCH 5.4 104/131] scsi: target: core: Fix deadlock due to recursive locking Date: Mon, 9 Oct 2023 15:02:24 +0200 Message-ID: <20231009130119.601393073@linuxfoundation.org> X-Mailer: git-send-email 2.42.0 In-Reply-To: <20231009130116.329529591@linuxfoundation.org> References: <20231009130116.329529591@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org 5.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Junxiao Bi [ Upstream commit a154f5f643c6ecddd44847217a7a3845b4350003 ] The following call trace shows a deadlock issue due to recursive locking of mutex "device_mutex". First lock acquire is in target_for_each_device() and second in target_free_device(). PID: 148266 TASK: ffff8be21ffb5d00 CPU: 10 COMMAND: "iscsi_ttx" #0 [ffffa2bfc9ec3b18] __schedule at ffffffffa8060e7f #1 [ffffa2bfc9ec3ba0] schedule at ffffffffa8061224 #2 [ffffa2bfc9ec3bb8] schedule_preempt_disabled at ffffffffa80615ee #3 [ffffa2bfc9ec3bc8] __mutex_lock at ffffffffa8062fd7 #4 [ffffa2bfc9ec3c40] __mutex_lock_slowpath at ffffffffa80631d3 #5 [ffffa2bfc9ec3c50] mutex_lock at ffffffffa806320c #6 [ffffa2bfc9ec3c68] target_free_device at ffffffffc0935998 [target_core_mod] #7 [ffffa2bfc9ec3c90] target_core_dev_release at ffffffffc092f975 [target_core_mod] #8 [ffffa2bfc9ec3ca0] config_item_put at ffffffffa79d250f #9 [ffffa2bfc9ec3cd0] config_item_put at ffffffffa79d2583 #10 [ffffa2bfc9ec3ce0] target_devices_idr_iter at ffffffffc0933f3a [target_core_mod] #11 [ffffa2bfc9ec3d00] idr_for_each at ffffffffa803f6fc #12 [ffffa2bfc9ec3d60] target_for_each_device at ffffffffc0935670 [target_core_mod] #13 [ffffa2bfc9ec3d98] transport_deregister_session at ffffffffc0946408 [target_core_mod] #14 [ffffa2bfc9ec3dc8] iscsit_close_session at ffffffffc09a44a6 [iscsi_target_mod] #15 [ffffa2bfc9ec3df0] iscsit_close_connection at ffffffffc09a4a88 [iscsi_target_mod] #16 [ffffa2bfc9ec3df8] finish_task_switch at ffffffffa76e5d07 #17 [ffffa2bfc9ec3e78] iscsit_take_action_for_connection_exit at ffffffffc0991c23 [iscsi_target_mod] #18 [ffffa2bfc9ec3ea0] iscsi_target_tx_thread at ffffffffc09a403b [iscsi_target_mod] #19 [ffffa2bfc9ec3f08] kthread at ffffffffa76d8080 #20 [ffffa2bfc9ec3f50] ret_from_fork at ffffffffa8200364 Fixes: 36d4cb460bcb ("scsi: target: Avoid that EXTENDED COPY commands trigger lock inversion") Signed-off-by: Junxiao Bi Link: https://lore.kernel.org/r/20230918225848.66463-1-junxiao.bi@oracle.com Reviewed-by: Mike Christie Signed-off-by: Martin K. Petersen Signed-off-by: Sasha Levin --- drivers/target/target_core_device.c | 11 ++++------- 1 file changed, 4 insertions(+), 7 deletions(-) diff --git a/drivers/target/target_core_device.c b/drivers/target/target_core_device.c index 20fe287039857..8ba134ccd3b9c 100644 --- a/drivers/target/target_core_device.c +++ b/drivers/target/target_core_device.c @@ -856,7 +856,6 @@ sector_t target_to_linux_sector(struct se_device *dev, sector_t lb) EXPORT_SYMBOL(target_to_linux_sector); struct devices_idr_iter { - struct config_item *prev_item; int (*fn)(struct se_device *dev, void *data); void *data; }; @@ -866,11 +865,9 @@ static int target_devices_idr_iter(int id, void *p, void *data) { struct devices_idr_iter *iter = data; struct se_device *dev = p; + struct config_item *item; int ret; - config_item_put(iter->prev_item); - iter->prev_item = NULL; - /* * We add the device early to the idr, so it can be used * by backend modules during configuration. We do not want @@ -880,12 +877,13 @@ static int target_devices_idr_iter(int id, void *p, void *data) if (!target_dev_configured(dev)) return 0; - iter->prev_item = config_item_get_unless_zero(&dev->dev_group.cg_item); - if (!iter->prev_item) + item = config_item_get_unless_zero(&dev->dev_group.cg_item); + if (!item) return 0; mutex_unlock(&device_mutex); ret = iter->fn(dev, iter->data); + config_item_put(item); mutex_lock(&device_mutex); return ret; @@ -908,7 +906,6 @@ int target_for_each_device(int (*fn)(struct se_device *dev, void *data), mutex_lock(&device_mutex); ret = idr_for_each(&devices_idr, target_devices_idr_iter, &iter); mutex_unlock(&device_mutex); - config_item_put(iter.prev_item); return ret; } -- 2.40.1