From patchwork Mon May 8 16:22:19 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Maurizio Lombardi X-Patchwork-Id: 13234754 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 771AEC77B7F for ; Mon, 8 May 2023 16:23:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233714AbjEHQXR (ORCPT ); Mon, 8 May 2023 12:23:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54716 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232527AbjEHQXP (ORCPT ); Mon, 8 May 2023 12:23:15 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DD0483593 for ; Mon, 8 May 2023 09:22:29 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1683562949; 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: in-reply-to:in-reply-to:references:references; bh=lhidUOW4bA7y2e2ETgcoqxr4iJ8kArDkcOif0PbdN+A=; b=Qcm5HBGw/BxwykKJlmNmDka4bb/HKRROsmKF1WK2NWVJ42mo65td42ByfzFUbNpuwwyNNQ cOosP+RkKQ2XqF+C0n5moCCInIwqIjFDHzbRI1Mng01FHWsTRBBp5nDk3EhqH9BqsoWzrp +oh5Hlgw8rVMGLAq8VAdU4Zebxj6y6E= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-1-GcrJSZ59Nfa-msN5CI94sg-1; Mon, 08 May 2023 12:22:27 -0400 X-MC-Unique: GcrJSZ59Nfa-msN5CI94sg-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.rdu2.redhat.com [10.11.54.4]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 4775B870828; Mon, 8 May 2023 16:22:27 +0000 (UTC) Received: from kalibr.redhat.com (unknown [10.35.206.135]) by smtp.corp.redhat.com (Postfix) with ESMTP id 130382026D16; Mon, 8 May 2023 16:22:25 +0000 (UTC) From: Maurizio Lombardi To: martin.petersen@oracle.com Cc: michael.christie@oracle.com, target-devel@vger.kernel.org Subject: [PATCH V3 3/3] target: iscsi: prevent login threads from racing between each other Date: Mon, 8 May 2023 18:22:19 +0200 Message-Id: <20230508162219.1731964-4-mlombard@redhat.com> In-Reply-To: <20230508162219.1731964-1-mlombard@redhat.com> References: <20230508162219.1731964-1-mlombard@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.4 Precedence: bulk List-ID: X-Mailing-List: target-devel@vger.kernel.org The tpg->np_login_sem is a semaphore that is used to serialize the login process when multiple login threads run concurrently against the same target portal group. The iscsi_target_locate_portal() function finds the tpg, calls iscsit_access_np() against the np_login_sem semaphore and saves the tpg pointer in conn->tpg; If iscsi_target_locate_portal() fails, the caller will check for the conn->tpg pointer and, if it's not NULL, then it will assume that iscsi_target_locate_portal() called iscsit_access_np() on the semaphore. Make sure that conn->tpg gets initialized only if iscsit_access_np() was successful, otherwise iscsit_deaccess_np() may end up being called against a semaphore we never took, allowing more than one thread to access the same tpg. Signed-off-by: Maurizio Lombardi --- drivers/target/iscsi/iscsi_target_nego.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/target/iscsi/iscsi_target_nego.c b/drivers/target/iscsi/iscsi_target_nego.c index e3a5644a70b3..fa3fb5f4e6bc 100644 --- a/drivers/target/iscsi/iscsi_target_nego.c +++ b/drivers/target/iscsi/iscsi_target_nego.c @@ -1122,6 +1122,7 @@ int iscsi_target_locate_portal( iscsi_target_set_sock_callbacks(conn); login->np = np; + conn->tpg = NULL; login_req = (struct iscsi_login_req *) login->req; payload_length = ntoh24(login_req->dlength); @@ -1189,7 +1190,6 @@ int iscsi_target_locate_portal( */ sessiontype = strncmp(s_buf, DISCOVERY, 9); if (!sessiontype) { - conn->tpg = iscsit_global->discovery_tpg; if (!login->leading_connection) goto get_target; @@ -1206,9 +1206,11 @@ int iscsi_target_locate_portal( * Serialize access across the discovery struct iscsi_portal_group to * process login attempt. */ + conn->tpg = iscsit_global->discovery_tpg; if (iscsit_access_np(np, conn->tpg) < 0) { iscsit_tx_login_rsp(conn, ISCSI_STATUS_CLS_TARGET_ERR, ISCSI_LOGIN_STATUS_SVC_UNAVAILABLE); + conn->tpg = NULL; ret = -1; goto out; }