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| author | Nicholas Bellinger <nab@linux-iscsi.org> | 2016-01-19 16:15:27 -0800 |
|---|---|---|
| committer | Nicholas Bellinger <nab@linux-iscsi.org> | 2016-01-20 01:33:55 -0800 |
| commit | 26a99c19f810b2593410899a5b304b21b47428a6 (patch) | |
| tree | 50cac8c52b719b753b30c5d275bc803d44e07049 /drivers/target | |
| parent | f246c941549c715a66a4477c3053569b2f5b8823 (diff) | |
| download | linux-26a99c19f810b2593410899a5b304b21b47428a6.tar.bz2 | |
iscsi-target: Fix potential dead-lock during node acl delete
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>
Cc: stable@vger.kernel.org # 3.10+
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Diffstat (limited to 'drivers/target')
| -rw-r--r-- | drivers/target/iscsi/iscsi_target_configfs.c | 16 |
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; } |