Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753272AbaBGLZL (ORCPT ); Fri, 7 Feb 2014 06:25:11 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:41167 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753254AbaBGLZI (ORCPT ); Fri, 7 Feb 2014 06:25:08 -0500 From: Luis Henriques To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Andy Grover , Nicholas Bellinger , Luis Henriques Subject: [PATCH 3.5 72/88] target/iscsi: Fix network portal creation race Date: Fri, 7 Feb 2014 11:23:09 +0000 Message-Id: <1391772205-22239-73-git-send-email-luis.henriques@canonical.com> X-Mailer: git-send-email 1.8.3.2 In-Reply-To: <1391772205-22239-1-git-send-email-luis.henriques@canonical.com> References: <1391772205-22239-1-git-send-email-luis.henriques@canonical.com> X-Extended-Stable: 3.5 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.5.7.30 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Andy Grover commit ee291e63293146db64668e8d65eb35c97e8324f4 upstream. When creating network portals rapidly, such as when restoring a configuration, LIO's code to reuse existing portals can return a false negative if the thread hasn't run yet and set np_thread_state to ISCSI_NP_THREAD_ACTIVE. This causes an error in the network stack when attempting to bind to the same address/port. This patch sets NP_THREAD_ACTIVE before the np is placed on g_np_list, so even if the thread hasn't run yet, iscsit_get_np will return the existing np. Also, convert np_lock -> np_mutex + hold across adding new net portal to g_np_list to prevent a race where two threads may attempt to create the same network portal, resulting in one of them failing. (nab: Add missing mutex_unlocks in iscsit_add_np failure paths) (DanC: Fix incorrect spin_unlock -> spin_unlock_bh) Signed-off-by: Andy Grover Signed-off-by: Nicholas Bellinger [ luis: backported to 3.5: adjusted context ] Signed-off-by: Luis Henriques --- drivers/target/iscsi/iscsi_target.c | 34 +++++++++++++++++++++------------- 1 file changed, 21 insertions(+), 13 deletions(-) diff --git a/drivers/target/iscsi/iscsi_target.c b/drivers/target/iscsi/iscsi_target.c index 955392e..6e270f9 100644 --- a/drivers/target/iscsi/iscsi_target.c +++ b/drivers/target/iscsi/iscsi_target.c @@ -52,7 +52,7 @@ static LIST_HEAD(g_tiqn_list); static LIST_HEAD(g_np_list); static DEFINE_SPINLOCK(tiqn_lock); -static DEFINE_SPINLOCK(np_lock); +static DEFINE_MUTEX(np_lock); static struct idr tiqn_idr; struct idr sess_idr; @@ -264,6 +264,9 @@ int iscsit_deaccess_np(struct iscsi_np *np, struct iscsi_portal_group *tpg) return 0; } +/* + * Called with mutex np_lock held + */ static struct iscsi_np *iscsit_get_np( struct __kernel_sockaddr_storage *sockaddr, int network_transport) @@ -274,11 +277,10 @@ static struct iscsi_np *iscsit_get_np( int ip_match = 0; u16 port; - spin_lock_bh(&np_lock); list_for_each_entry(np, &g_np_list, np_list) { - spin_lock(&np->np_thread_lock); + spin_lock_bh(&np->np_thread_lock); if (np->np_thread_state != ISCSI_NP_THREAD_ACTIVE) { - spin_unlock(&np->np_thread_lock); + spin_unlock_bh(&np->np_thread_lock); continue; } @@ -311,13 +313,11 @@ static struct iscsi_np *iscsit_get_np( * while iscsi_tpg_add_network_portal() is called. */ np->np_exports++; - spin_unlock(&np->np_thread_lock); - spin_unlock_bh(&np_lock); + spin_unlock_bh(&np->np_thread_lock); return np; } - spin_unlock(&np->np_thread_lock); + spin_unlock_bh(&np->np_thread_lock); } - spin_unlock_bh(&np_lock); return NULL; } @@ -331,16 +331,22 @@ struct iscsi_np *iscsit_add_np( struct sockaddr_in6 *sock_in6; struct iscsi_np *np; int ret; + + mutex_lock(&np_lock); + /* * Locate the existing struct iscsi_np if already active.. */ np = iscsit_get_np(sockaddr, network_transport); - if (np) + if (np) { + mutex_unlock(&np_lock); return np; + } np = kzalloc(sizeof(struct iscsi_np), GFP_KERNEL); if (!np) { pr_err("Unable to allocate memory for struct iscsi_np\n"); + mutex_unlock(&np_lock); return ERR_PTR(-ENOMEM); } @@ -363,6 +369,7 @@ struct iscsi_np *iscsit_add_np( ret = iscsi_target_setup_login_socket(np, sockaddr); if (ret != 0) { kfree(np); + mutex_unlock(&np_lock); return ERR_PTR(ret); } @@ -371,6 +378,7 @@ struct iscsi_np *iscsit_add_np( pr_err("Unable to create kthread: iscsi_np\n"); ret = PTR_ERR(np->np_thread); kfree(np); + mutex_unlock(&np_lock); return ERR_PTR(ret); } /* @@ -381,10 +389,10 @@ struct iscsi_np *iscsit_add_np( * point because iscsi_np has not been added to g_np_list yet. */ np->np_exports = 1; + np->np_thread_state = ISCSI_NP_THREAD_ACTIVE; - spin_lock_bh(&np_lock); list_add_tail(&np->np_list, &g_np_list); - spin_unlock_bh(&np_lock); + mutex_unlock(&np_lock); pr_debug("CORE[0] - Added Network Portal: %s:%hu on %s\n", np->np_ip, np->np_port, (np->np_network_transport == ISCSI_TCP) ? @@ -455,9 +463,9 @@ int iscsit_del_np(struct iscsi_np *np) } iscsit_del_np_comm(np); - spin_lock_bh(&np_lock); + mutex_lock(&np_lock); list_del(&np->np_list); - spin_unlock_bh(&np_lock); + mutex_unlock(&np_lock); pr_debug("CORE[0] - Removed Network Portal: %s:%hu on %s\n", np->np_ip, np->np_port, (np->np_network_transport == ISCSI_TCP) ? -- 1.8.3.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/