From: Bart Van Assche <bart.vanassche@wdc.com>
Date: Tue, 31 Oct 2017 18:03:17 +0000 (-0700)
Subject: target/iscsi: Fix a race condition in iscsit_add_reject_from_cmd()
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=cfe2b621bb18d86e93271febf8c6e37622da2d14;p=linux.git

target/iscsi: Fix a race condition in iscsit_add_reject_from_cmd()

Avoid that cmd->se_cmd.se_tfo is read after a command has already been
freed.

Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Mike Christie <mchristi@redhat.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
---

diff --git a/drivers/target/iscsi/iscsi_target.c b/drivers/target/iscsi/iscsi_target.c
index 91fbada7cdc20..541f66a875fcf 100644
--- a/drivers/target/iscsi/iscsi_target.c
+++ b/drivers/target/iscsi/iscsi_target.c
@@ -833,6 +833,7 @@ static int iscsit_add_reject_from_cmd(
 	unsigned char *buf)
 {
 	struct iscsi_conn *conn;
+	const bool do_put = cmd->se_cmd.se_tfo != NULL;
 
 	if (!cmd->conn) {
 		pr_err("cmd->conn is NULL for ITT: 0x%08x\n",
@@ -863,7 +864,7 @@ static int iscsit_add_reject_from_cmd(
 	 * Perform the kref_put now if se_cmd has already been setup by
 	 * scsit_setup_scsi_cmd()
 	 */
-	if (cmd->se_cmd.se_tfo != NULL) {
+	if (do_put) {
 		pr_debug("iscsi reject: calling target_put_sess_cmd >>>>>>\n");
 		target_put_sess_cmd(&cmd->se_cmd);
 	}