From a656183e6c58a3a4d818278afab522b30a17014c Mon Sep 17 00:00:00 2001 From: Lee Duncan Date: Mon, 25 Feb 2019 09:41:30 -0800 Subject: scsi: libiscsi: Hold back_lock when calling iscsi_complete_task If there is an error queueing an iscsi command in iscsi_queuecommand(), for example if the transport fails to take the command in sessuin->tt->xmit_task(), then the error path can call iscsi_complete_task() without first aquiring the back_lock as required. This can lead to things like ITT pool can get corrupt, resulting in duplicate ITTs being sent out. The solution is to hold the back_lock around iscsi_complete_task() calls, and to add a little commenting to help others understand when back_lock must be held. Signed-off-by: Lee Duncan Acked-by: Chris Leech Signed-off-by: Martin K. Petersen --- drivers/scsi/libiscsi.c | 22 ++++++++++++++++++++-- 1 file changed, 20 insertions(+), 2 deletions(-) (limited to 'drivers/scsi') diff --git a/drivers/scsi/libiscsi.c b/drivers/scsi/libiscsi.c index dd314d2b1111..418dbed7618f 100644 --- a/drivers/scsi/libiscsi.c +++ b/drivers/scsi/libiscsi.c @@ -798,7 +798,7 @@ EXPORT_SYMBOL_GPL(iscsi_conn_send_pdu); * @datalen: len of buffer * * iscsi_cmd_rsp sets up the scsi_cmnd fields based on the PDU and - * then completes the command and task. + * then completes the command and task. called under back_lock **/ static void iscsi_scsi_cmd_rsp(struct iscsi_conn *conn, struct iscsi_hdr *hdr, struct iscsi_task *task, char *data, @@ -894,6 +894,9 @@ out: * @conn: iscsi connection * @hdr: iscsi pdu * @task: scsi command task + * + * iscsi_data_in_rsp sets up the scsi_cmnd fields based on the data received + * then completes the command and task. called under back_lock **/ static void iscsi_data_in_rsp(struct iscsi_conn *conn, struct iscsi_hdr *hdr, @@ -978,6 +981,16 @@ static int iscsi_send_nopout(struct iscsi_conn *conn, struct iscsi_nopin *rhdr) return 0; } +/** + * iscsi_nop_out_rsp - SCSI NOP Response processing + * @task: scsi command task + * @nop: the nop structure + * @data: where to put the data + * @datalen: length of data + * + * iscsi_nop_out_rsp handles nop response from use or + * from user space. called under back_lock + **/ static int iscsi_nop_out_rsp(struct iscsi_task *task, struct iscsi_nopin *nop, char *data, int datalen) { @@ -1744,7 +1757,9 @@ int iscsi_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *sc) return 0; prepd_reject: + spin_lock_bh(&session->back_lock); iscsi_complete_task(task, ISCSI_TASK_REQUEUE_SCSIQ); + spin_unlock_bh(&session->back_lock); reject: spin_unlock_bh(&session->frwd_lock); ISCSI_DBG_SESSION(session, "cmd 0x%x rejected (%d)\n", @@ -1752,7 +1767,9 @@ reject: return SCSI_MLQUEUE_TARGET_BUSY; prepd_fault: + spin_lock_bh(&session->back_lock); iscsi_complete_task(task, ISCSI_TASK_REQUEUE_SCSIQ); + spin_unlock_bh(&session->back_lock); fault: spin_unlock_bh(&session->frwd_lock); ISCSI_DBG_SESSION(session, "iscsi: cmd 0x%x is not queued (%d)\n", @@ -3069,8 +3086,9 @@ fail_mgmt_tasks(struct iscsi_session *session, struct iscsi_conn *conn) state = ISCSI_TASK_ABRT_SESS_RECOV; if (task->state == ISCSI_TASK_PENDING) state = ISCSI_TASK_COMPLETED; + spin_lock_bh(&session->back_lock); iscsi_complete_task(task, state); - + spin_unlock_bh(&session->back_lock); } } -- cgit v1.2.3