This is a note to let you know that I've just added the patch titled iscsi-target: Fix potential dead-lock during node acl delete to the 3.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: iscsi-target-fix-potential-dead-lock-during-node-acl-delete.patch and it can be found in the queue-3.14 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 26a99c19f810b2593410899a5b304b21b47428a6 Mon Sep 17 00:00:00 2001 From: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx> Date: Tue, 19 Jan 2016 16:15:27 -0800 Subject: iscsi-target: Fix potential dead-lock during node acl delete From: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx> commit 26a99c19f810b2593410899a5b304b21b47428a6 upstream. This patch is a iscsi-target specific bug-fix for a dead-lock that can occur during explicit struct se_node_acl->acl_group se_session deletion via configfs rmdir(2), when iscsi-target time2retain timer is still active. It changes iscsi-target to obtain se_portal_group->session_lock internally using spin_in_locked() to check for the specific se_node_acl configfs shutdown rmdir(2) case. Note this patch is intended for stable, and the subsequent v4.5-rc patch converts target_core_tpg.c to use proper se_sess->sess_kref reference counting for both se_node_acl deletion + se_node_acl->queue_depth se_session restart. Reported-by:: Sagi Grimberg <sagig@xxxxxxxxxxxx> Cc: Christoph Hellwig <hch@xxxxxx> Cc: Hannes Reinecke <hare@xxxxxxx> Cc: Andy Grover <agrover@xxxxxxxxxx> Cc: Mike Christie <michaelc@xxxxxxxxxxx> Signed-off-by: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/target/iscsi/iscsi_target_configfs.c | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-) --- a/drivers/target/iscsi/iscsi_target_configfs.c +++ b/drivers/target/iscsi/iscsi_target_configfs.c @@ -1876,7 +1876,8 @@ static void lio_tpg_release_fabric_acl( } /* - * Called with spin_lock_bh(struct se_portal_group->session_lock) held.. + * Called with spin_lock_irq(struct se_portal_group->session_lock) held + * or not held. * * Also, this function calls iscsit_inc_session_usage_count() on the * struct iscsi_session in question. @@ -1884,19 +1885,32 @@ static void lio_tpg_release_fabric_acl( static int lio_tpg_shutdown_session(struct se_session *se_sess) { struct iscsi_session *sess = se_sess->fabric_sess_ptr; + struct se_portal_group *se_tpg = se_sess->se_tpg; + bool local_lock = false; + + if (!spin_is_locked(&se_tpg->session_lock)) { + spin_lock_irq(&se_tpg->session_lock); + local_lock = true; + } spin_lock(&sess->conn_lock); if (atomic_read(&sess->session_fall_back_to_erl0) || atomic_read(&sess->session_logout) || (sess->time2retain_timer_flags & ISCSI_TF_EXPIRED)) { spin_unlock(&sess->conn_lock); + if (local_lock) + spin_unlock_irq(&sess->conn_lock); return 0; } atomic_set(&sess->session_reinstatement, 1); spin_unlock(&sess->conn_lock); iscsit_stop_time2retain_timer(sess); + spin_unlock_irq(&se_tpg->session_lock); + iscsit_stop_session(sess, 1, 1); + if (!local_lock) + spin_lock_irq(&se_tpg->session_lock); return 1; } Patches currently in stable-queue which might be from nab@xxxxxxxxxxxxxxx are queue-3.14/iscsi-target-fix-rx_login_comp-hang-after-login-failure.patch queue-3.14/iscsi-target-fix-potential-dead-lock-during-node-acl-delete.patch -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html