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=-11.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham 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 E35A6C43466 for ; Mon, 21 Sep 2020 16:32:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B24D8239A1 for ; Mon, 21 Sep 2020 16:32:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600705944; bh=c5rXe6L+Uv7p3TCLj0B2Tm3NmbfuKM53pvoUknxnlVI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=xiheBGTfchLwG6GU+qWKUv3w78Pa74sF0oRqk9fzFwBJiaN0OEBTWQctBrMKh+SfW sLmYae6EGnwj6WX9/tr7fHyAV21Od5uW/jB5CyscC89HTpsnpOtuTdaB0WiNputlJS e1jQgFQ7ra9dy8SvblIxkj3Q1Tx4vpnAa9oB0qFU= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728456AbgIUQcX (ORCPT ); Mon, 21 Sep 2020 12:32:23 -0400 Received: from mail.kernel.org ([198.145.29.99]:57340 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728246AbgIUQcG (ORCPT ); Mon, 21 Sep 2020 12:32:06 -0400 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id C10EA23998; Mon, 21 Sep 2020 16:32:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600705925; bh=c5rXe6L+Uv7p3TCLj0B2Tm3NmbfuKM53pvoUknxnlVI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=gOzj0+xuTXcwtA4O8cbSogxtfZPfXl6YlbnGG1ayl5pe3OddemNSbcnhkbe178iRc ywxj8OFLNZYHAHt0OkwVzeJUbDdU+UJNFkj29xs0pAdK+jMHpN4leEux9yiDMizhV+ 8G42xUbXIhlytObTzVTGDAgTe4kzBWlbwmIPca6M= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Mike Christie , Hou Pu , "Martin K. Petersen" Subject: [PATCH 4.4 18/46] scsi: target: iscsi: Fix hang in iscsit_access_np() when getting tpg->np_login_sem Date: Mon, 21 Sep 2020 18:27:34 +0200 Message-Id: <20200921162034.165342926@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200921162033.346434578@linuxfoundation.org> References: <20200921162033.346434578@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Hou Pu commit ed43ffea78dcc97db3f561da834f1a49c8961e33 upstream. The iSCSI target login thread might get stuck with the following stack: cat /proc/`pidof iscsi_np`/stack [<0>] down_interruptible+0x42/0x50 [<0>] iscsit_access_np+0xe3/0x167 [<0>] iscsi_target_locate_portal+0x695/0x8ac [<0>] __iscsi_target_login_thread+0x855/0xb82 [<0>] iscsi_target_login_thread+0x2f/0x5a [<0>] kthread+0xfa/0x130 [<0>] ret_from_fork+0x1f/0x30 This can be reproduced via the following steps: 1. Initiator A tries to log in to iqn1-tpg1 on port 3260. After finishing PDU exchange in the login thread and before the negotiation is finished the the network link goes down. At this point A has not finished login and tpg->np_login_sem is held. 2. Initiator B tries to log in to iqn2-tpg1 on port 3260. After finishing PDU exchange in the login thread the target expects to process remaining login PDUs in workqueue context. 3. Initiator A' tries to log in to iqn1-tpg1 on port 3260 from a new socket. A' will wait for tpg->np_login_sem with np->np_login_timer loaded to wait for at most 15 seconds. The lock is held by A so A' eventually times out. 4. Before A' got timeout initiator B gets negotiation failed and calls iscsi_target_login_drop()->iscsi_target_login_sess_out(). The np->np_login_timer is canceled and initiator A' will hang forever. Because A' is now in the login thread, no new login requests can be serviced. Fix this by moving iscsi_stop_login_thread_timer() out of iscsi_target_login_sess_out(). Also remove iscsi_np parameter from iscsi_target_login_sess_out(). Link: https://lore.kernel.org/r/20200729130343.24976-1-houpu@bytedance.com Cc: stable@vger.kernel.org Reviewed-by: Mike Christie Signed-off-by: Hou Pu Signed-off-by: Martin K. Petersen Signed-off-by: Greg Kroah-Hartman --- drivers/target/iscsi/iscsi_target_login.c | 6 +++--- drivers/target/iscsi/iscsi_target_login.h | 3 +-- drivers/target/iscsi/iscsi_target_nego.c | 3 +-- 3 files changed, 5 insertions(+), 7 deletions(-) --- a/drivers/target/iscsi/iscsi_target_login.c +++ b/drivers/target/iscsi/iscsi_target_login.c @@ -1139,7 +1139,7 @@ iscsit_conn_set_transport(struct iscsi_c } void iscsi_target_login_sess_out(struct iscsi_conn *conn, - struct iscsi_np *np, bool zero_tsih, bool new_sess) + bool zero_tsih, bool new_sess) { if (!new_sess) goto old_sess_out; @@ -1161,7 +1161,6 @@ void iscsi_target_login_sess_out(struct conn->sess = NULL; old_sess_out: - iscsi_stop_login_thread_timer(np); /* * If login negotiation fails check if the Time2Retain timer * needs to be restarted. @@ -1407,8 +1406,9 @@ static int __iscsi_target_login_thread(s new_sess_out: new_sess = true; old_sess_out: + iscsi_stop_login_thread_timer(np); tpg_np = conn->tpg_np; - iscsi_target_login_sess_out(conn, np, zero_tsih, new_sess); + iscsi_target_login_sess_out(conn, zero_tsih, new_sess); new_sess = false; if (tpg) { --- a/drivers/target/iscsi/iscsi_target_login.h +++ b/drivers/target/iscsi/iscsi_target_login.h @@ -14,8 +14,7 @@ extern int iscsit_put_login_tx(struct is extern void iscsit_free_conn(struct iscsi_np *, struct iscsi_conn *); extern int iscsit_start_kthreads(struct iscsi_conn *); extern void iscsi_post_login_handler(struct iscsi_np *, struct iscsi_conn *, u8); -extern void iscsi_target_login_sess_out(struct iscsi_conn *, struct iscsi_np *, - bool, bool); +extern void iscsi_target_login_sess_out(struct iscsi_conn *, bool, bool); extern int iscsi_target_login_thread(void *); #endif /*** ISCSI_TARGET_LOGIN_H ***/ --- a/drivers/target/iscsi/iscsi_target_nego.c +++ b/drivers/target/iscsi/iscsi_target_nego.c @@ -547,12 +547,11 @@ static bool iscsi_target_sk_check_and_cl static void iscsi_target_login_drop(struct iscsi_conn *conn, struct iscsi_login *login) { - struct iscsi_np *np = login->np; bool zero_tsih = login->zero_tsih; iscsi_remove_failed_auth_entry(conn); iscsi_target_nego_release(conn); - iscsi_target_login_sess_out(conn, np, zero_tsih, true); + iscsi_target_login_sess_out(conn, zero_tsih, true); } static void iscsi_target_login_timeout(unsigned long data)