The tpg->np_login_sem is a semaphore that is used to serialize the login
process when multiple login threads run concurrently against the same
target portal group.
The iscsi_target_locate_portal() function finds the tpg,
calls iscsit_access_np() against the np_login_sem semaphore
and saves the tpg pointer in conn->tpg;
If iscsi_target_locate_portal() fails, the caller will check for the
conn->tpg pointer and, if it's not NULL, then it will assume
that iscsi_target_locate_portal() called iscsit_access_np() on the
semaphore.
Make sure that conn->tpg gets initialized only if iscsit_access_np()
was successful, otherwise iscsit_deaccess_np() may end up
being called against a semaphore we never took, allowing more than one
thread to access the same tpg.
Signed-off-by: Maurizio Lombardi <mlombard@xxxxxxxxxx>
---
drivers/target/iscsi/iscsi_target_nego.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/target/iscsi/iscsi_target_nego.c b/drivers/target/iscsi/iscsi_target_nego.c
index e3a5644a70b3..fa3fb5f4e6bc 100644
--- a/drivers/target/iscsi/iscsi_target_nego.c
+++ b/drivers/target/iscsi/iscsi_target_nego.c
@@ -1122,6 +1122,7 @@ int iscsi_target_locate_portal(
iscsi_target_set_sock_callbacks(conn);
login->np = np;
+ conn->tpg = NULL;
login_req = (struct iscsi_login_req *) login->req;
payload_length = ntoh24(login_req->dlength);
@@ -1189,7 +1190,6 @@ int iscsi_target_locate_portal(
*/
sessiontype = strncmp(s_buf, DISCOVERY, 9);
if (!sessiontype) {
- conn->tpg = iscsit_global->discovery_tpg;
if (!login->leading_connection)
goto get_target;
@@ -1206,9 +1206,11 @@ int iscsi_target_locate_portal(
* Serialize access across the discovery struct iscsi_portal_group to
* process login attempt.
*/
+ conn->tpg = iscsit_global->discovery_tpg;
if (iscsit_access_np(np, conn->tpg) < 0) {
iscsit_tx_login_rsp(conn, ISCSI_STATUS_CLS_TARGET_ERR,
ISCSI_LOGIN_STATUS_SVC_UNAVAILABLE);
+ conn->tpg = NULL;
ret = -1;
goto out;
}
--
2.31.1
