summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorNicholas Bellinger <nab@linux-iscsi.org>2016-06-02 14:56:45 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2016-08-20 18:09:26 +0200
commitf318588b758514c35f0a9227195178a3b2b4b733 (patch)
tree16fc95e051b89945066202e8d27e1776c497f256
parent60ba156dda2c11ff7a44d78ec64abd21b9813115 (diff)
downloadlwn-f318588b758514c35f0a9227195178a3b2b4b733.tar.gz
lwn-f318588b758514c35f0a9227195178a3b2b4b733.zip
target: Fix race between iscsi-target connection shutdown + ABORT_TASK
commit 064cdd2d91c2805d788876082f31cc63506f22c3 upstream. This patch fixes a race in iscsit_release_commands_from_conn() -> iscsit_free_cmd() -> transport_generic_free_cmd() + wait_for_tasks=1, where CMD_T_FABRIC_STOP could end up being set after the final kref_put() is called from core_tmr_abort_task() context. This results in transport_generic_free_cmd() blocking indefinately on se_cmd->cmd_wait_comp, because the target_release_cmd_kref() check for CMD_T_FABRIC_STOP returns false. To address this bug, make iscsit_release_commands_from_conn() do list_splice and set CMD_T_FABRIC_STOP early while holding iscsi_conn->cmd_lock. Also make iscsit_aborted_task() only remove iscsi_cmd_t if CMD_T_FABRIC_STOP has not already been set. Finally in target_release_cmd_kref(), only honor fabric_stop if CMD_T_ABORTED has been set. Cc: Mike Christie <mchristi@redhat.com> Cc: Quinn Tran <quinn.tran@qlogic.com> Cc: Himanshu Madhani <himanshu.madhani@qlogic.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Hannes Reinecke <hare@suse.de> Tested-by: Nicholas Bellinger <nab@linux-iscsi.org> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--drivers/target/iscsi/iscsi_target.c22
-rw-r--r--drivers/target/target_core_transport.c3
2 files changed, 18 insertions, 7 deletions
diff --git a/drivers/target/iscsi/iscsi_target.c b/drivers/target/iscsi/iscsi_target.c
index 72204fbf2bb1..bd810c109277 100644
--- a/drivers/target/iscsi/iscsi_target.c
+++ b/drivers/target/iscsi/iscsi_target.c
@@ -492,7 +492,8 @@ static void iscsit_aborted_task(struct iscsi_conn *conn, struct iscsi_cmd *cmd)
bool scsi_cmd = (cmd->iscsi_opcode == ISCSI_OP_SCSI_CMD);
spin_lock_bh(&conn->cmd_lock);
- if (!list_empty(&cmd->i_conn_node))
+ if (!list_empty(&cmd->i_conn_node) &&
+ !(cmd->se_cmd.transport_state & CMD_T_FABRIC_STOP))
list_del_init(&cmd->i_conn_node);
spin_unlock_bh(&conn->cmd_lock);
@@ -4194,6 +4195,7 @@ transport_err:
static void iscsit_release_commands_from_conn(struct iscsi_conn *conn)
{
+ LIST_HEAD(tmp_list);
struct iscsi_cmd *cmd = NULL, *cmd_tmp = NULL;
struct iscsi_session *sess = conn->sess;
/*
@@ -4202,18 +4204,26 @@ static void iscsit_release_commands_from_conn(struct iscsi_conn *conn)
* has been reset -> returned sleeping pre-handler state.
*/
spin_lock_bh(&conn->cmd_lock);
- list_for_each_entry_safe(cmd, cmd_tmp, &conn->conn_cmd_list, i_conn_node) {
+ list_splice_init(&conn->conn_cmd_list, &tmp_list);
+ list_for_each_entry(cmd, &tmp_list, i_conn_node) {
+ struct se_cmd *se_cmd = &cmd->se_cmd;
+
+ if (se_cmd->se_tfo != NULL) {
+ spin_lock(&se_cmd->t_state_lock);
+ se_cmd->transport_state |= CMD_T_FABRIC_STOP;
+ spin_unlock(&se_cmd->t_state_lock);
+ }
+ }
+ spin_unlock_bh(&conn->cmd_lock);
+
+ list_for_each_entry_safe(cmd, cmd_tmp, &tmp_list, i_conn_node) {
list_del_init(&cmd->i_conn_node);
- spin_unlock_bh(&conn->cmd_lock);
iscsit_increment_maxcmdsn(cmd, sess);
-
iscsit_free_cmd(cmd, true);
- spin_lock_bh(&conn->cmd_lock);
}
- spin_unlock_bh(&conn->cmd_lock);
}
static void iscsit_stop_timers_for_cmds(
diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c
index 93fb7c0dfa3c..8bd7bf6cd986 100644
--- a/drivers/target/target_core_transport.c
+++ b/drivers/target/target_core_transport.c
@@ -2543,7 +2543,8 @@ static void target_release_cmd_kref(struct kref *kref)
spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
spin_lock(&se_cmd->t_state_lock);
- fabric_stop = (se_cmd->transport_state & CMD_T_FABRIC_STOP);
+ fabric_stop = (se_cmd->transport_state & CMD_T_FABRIC_STOP) &&
+ (se_cmd->transport_state & CMD_T_ABORTED);
spin_unlock(&se_cmd->t_state_lock);
if (se_cmd->cmd_wait_set || fabric_stop) {