From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B4A84199B1 for ; Mon, 9 Oct 2023 13:25:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="KK4oYtd8" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2BC56C433C7; Mon, 9 Oct 2023 13:25:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1696857931; bh=twZfIK/qZfcRn4eNiogHNJxrAg8on6Vzx1M0qRgKPg0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=KK4oYtd8XCGZIn/c8OIetEwkAjG6CcfjaAsDzle1HdHPujNPr50/c7diPiS+5+lyc sWmC+ZVFzlyqaSRZ5I7jpvfc8dfuERyo1fXorsAg9IZCDHbJdfbWTcIa4nssOg9ntP 6WH6ahVCqeGSuFDoi30ma3CKQRmrbadntPLhaZ+Y= 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 5.15 39/75] scsi: target: core: Fix deadlock due to recursive locking Date: Mon, 9 Oct 2023 15:02:01 +0200 Message-ID: <20231009130112.600931608@linuxfoundation.org> X-Mailer: git-send-email 2.42.0 In-Reply-To: <20231009130111.200710898@linuxfoundation.org> References: <20231009130111.200710898@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.15-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 e18617371a9b2..813de805f815a 100644 --- a/drivers/target/target_core_device.c +++ b/drivers/target/target_core_device.c @@ -875,7 +875,6 @@ 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; }; @@ -885,11 +884,9 @@ 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 @@ -899,12 +896,13 @@ 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; @@ -927,7 +925,6 @@ 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