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authorNicholas Bellinger <nab@linux-iscsi.org>2016-01-19 16:15:27 -0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2016-02-25 12:01:16 -0800
commitdcec7af70910c48cba1e7b42383b9696356afc33 (patch)
tree92aad29f7611ccb61e401ca18dff04e10e6d7d16 /drivers/target/iscsi
parent954bb20f70ed1ab93406c6e01e1cd54d866c977e (diff)
iscsi-target: Fix potential dead-lock during node acl delete
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@mellanox.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Hannes Reinecke <hare@suse.de> Cc: Andy Grover <agrover@redhat.com> Cc: Mike Christie <michaelc@cs.wisc.edu> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/target/iscsi')
-rw-r--r--drivers/target/iscsi/iscsi_target_configfs.c16
1 files changed, 15 insertions, 1 deletions
diff --git a/drivers/target/iscsi/iscsi_target_configfs.c b/drivers/target/iscsi/iscsi_target_configfs.c
index 255204cc43e6..b4bfd706ac94 100644
--- a/drivers/target/iscsi/iscsi_target_configfs.c
+++ b/drivers/target/iscsi/iscsi_target_configfs.c
@@ -1593,7 +1593,8 @@ static int lio_tpg_check_prot_fabric_only(
}
/*
- * 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.
@@ -1601,19 +1602,32 @@ static int lio_tpg_check_prot_fabric_only(
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;
}