The patch below does not apply to the 4.9-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 106d45f350c7cac876844dc685845cba4ffdb70b Mon Sep 17 00:00:00 2001
From: Benjamin Block bblock@linux.ibm.com Date: Tue, 2 Jul 2019 23:02:01 +0200 Subject: [PATCH] scsi: zfcp: fix request object use-after-free in send path causing wrong traces
When tracing instances where we open and close WKA ports, we also pass the request-ID of the respective FSF command.
But after successfully sending the FSF command we must not use the request-object anymore, as this might result in an use-after-free (see "zfcp: fix request object use-after-free in send path causing seqno errors" ).
To fix this add a new variable that caches the request-ID before sending the request. This won't change during the hand-off to the FCP channel, and so it's safe to trace this cached request-ID later, instead of using the request object.
Signed-off-by: Benjamin Block bblock@linux.ibm.com Fixes: d27a7cb91960 ("zfcp: trace on request for open and close of WKA port") Cc: stable@vger.kernel.org #2.6.38+ Reviewed-by: Steffen Maier maier@linux.ibm.com Reviewed-by: Jens Remus jremus@linux.ibm.com Signed-off-by: Martin K. Petersen martin.petersen@oracle.com
diff --git a/drivers/s390/scsi/zfcp_fsf.c b/drivers/s390/scsi/zfcp_fsf.c index c5b2615b49ef..296bbc3c4606 100644 --- a/drivers/s390/scsi/zfcp_fsf.c +++ b/drivers/s390/scsi/zfcp_fsf.c @@ -1627,6 +1627,7 @@ int zfcp_fsf_open_wka_port(struct zfcp_fc_wka_port *wka_port) { struct zfcp_qdio *qdio = wka_port->adapter->qdio; struct zfcp_fsf_req *req; + unsigned long req_id = 0; int retval = -EIO;
spin_lock_irq(&qdio->req_q_lock); @@ -1649,6 +1650,8 @@ int zfcp_fsf_open_wka_port(struct zfcp_fc_wka_port *wka_port) hton24(req->qtcb->bottom.support.d_id, wka_port->d_id); req->data = wka_port;
+ req_id = req->req_id; + zfcp_fsf_start_timer(req, ZFCP_FSF_REQUEST_TIMEOUT); retval = zfcp_fsf_req_send(req); if (retval) @@ -1657,7 +1660,7 @@ int zfcp_fsf_open_wka_port(struct zfcp_fc_wka_port *wka_port) out: spin_unlock_irq(&qdio->req_q_lock); if (!retval) - zfcp_dbf_rec_run_wka("fsowp_1", wka_port, req->req_id); + zfcp_dbf_rec_run_wka("fsowp_1", wka_port, req_id); return retval; }
@@ -1683,6 +1686,7 @@ int zfcp_fsf_close_wka_port(struct zfcp_fc_wka_port *wka_port) { struct zfcp_qdio *qdio = wka_port->adapter->qdio; struct zfcp_fsf_req *req; + unsigned long req_id = 0; int retval = -EIO;
spin_lock_irq(&qdio->req_q_lock); @@ -1705,6 +1709,8 @@ int zfcp_fsf_close_wka_port(struct zfcp_fc_wka_port *wka_port) req->data = wka_port; req->qtcb->header.port_handle = wka_port->handle;
+ req_id = req->req_id; + zfcp_fsf_start_timer(req, ZFCP_FSF_REQUEST_TIMEOUT); retval = zfcp_fsf_req_send(req); if (retval) @@ -1713,7 +1719,7 @@ int zfcp_fsf_close_wka_port(struct zfcp_fc_wka_port *wka_port) out: spin_unlock_irq(&qdio->req_q_lock); if (!retval) - zfcp_dbf_rec_run_wka("fscwp_1", wka_port, req->req_id); + zfcp_dbf_rec_run_wka("fscwp_1", wka_port, req_id); return retval; }