diff options
| author | Maurizio Lombardi <mlombard@redhat.com> | 2023-05-08 18:22:19 +0200 |
|---|---|---|
| committer | Martin K. Petersen <martin.petersen@oracle.com> | 2023-05-22 16:29:39 -0400 |
| commit | 2a737d3b8c792400118d6cf94958f559de9c5e59 (patch) | |
| tree | 9cb285d2de6f933b26631433680762560a64fa8a | |
| parent | 98a8c2bf938a5973716f280da618077a3d255976 (diff) | |
scsi: target: iscsi: Prevent login threads from racing between each other
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@redhat.com>
Link: https://lore.kernel.org/r/20230508162219.1731964-4-mlombard@redhat.com
Reviewed-by: Mike Christie <michael.christie@oracle.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
| -rw-r--r-- | drivers/target/iscsi/iscsi_target_nego.c | 4 |
1 files changed, 3 insertions, 1 deletions
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; } |