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-rw-r--r--drivers/s390/scsi/zfcp_fsf.c45
1 files changed, 40 insertions, 5 deletions
diff --git a/drivers/s390/scsi/zfcp_fsf.c b/drivers/s390/scsi/zfcp_fsf.c
index d94496ee6883..c5b2615b49ef 100644
--- a/drivers/s390/scsi/zfcp_fsf.c
+++ b/drivers/s390/scsi/zfcp_fsf.c
@@ -11,6 +11,7 @@
#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
#include <linux/blktrace_api.h>
+#include <linux/types.h>
#include <linux/slab.h>
#include <scsi/fc/fc_els.h>
#include "zfcp_ext.h"
@@ -741,6 +742,7 @@ static struct zfcp_fsf_req *zfcp_fsf_req_create(struct zfcp_qdio *qdio,
static int zfcp_fsf_req_send(struct zfcp_fsf_req *req)
{
+ const bool is_srb = zfcp_fsf_req_is_status_read_buffer(req);
struct zfcp_adapter *adapter = req->adapter;
struct zfcp_qdio *qdio = adapter->qdio;
int req_id = req->req_id;
@@ -757,8 +759,20 @@ static int zfcp_fsf_req_send(struct zfcp_fsf_req *req)
return -EIO;
}
+ /*
+ * NOTE: DO NOT TOUCH ASYNC req PAST THIS POINT.
+ * ONLY TOUCH SYNC req AGAIN ON req->completion.
+ *
+ * The request might complete and be freed concurrently at any point
+ * now. This is not protected by the QDIO-lock (req_q_lock). So any
+ * uncontrolled access after this might result in an use-after-free bug.
+ * Only if the request doesn't have ZFCP_STATUS_FSFREQ_CLEANUP set, and
+ * when it is completed via req->completion, is it safe to use req
+ * again.
+ */
+
/* Don't increase for unsolicited status */
- if (!zfcp_fsf_req_is_status_read_buffer(req))
+ if (!is_srb)
adapter->fsf_req_seq_no++;
adapter->req_no++;
@@ -805,6 +819,7 @@ int zfcp_fsf_status_read(struct zfcp_qdio *qdio)
retval = zfcp_fsf_req_send(req);
if (retval)
goto failed_req_send;
+ /* NOTE: DO NOT TOUCH req PAST THIS POINT! */
goto out;
@@ -914,8 +929,10 @@ struct zfcp_fsf_req *zfcp_fsf_abort_fcp_cmnd(struct scsi_cmnd *scmnd)
req->qtcb->bottom.support.req_handle = (u64) old_req_id;
zfcp_fsf_start_timer(req, ZFCP_FSF_SCSI_ER_TIMEOUT);
- if (!zfcp_fsf_req_send(req))
+ if (!zfcp_fsf_req_send(req)) {
+ /* NOTE: DO NOT TOUCH req, UNTIL IT COMPLETES! */
goto out;
+ }
out_error_free:
zfcp_fsf_req_free(req);
@@ -1098,6 +1115,7 @@ int zfcp_fsf_send_ct(struct zfcp_fc_wka_port *wka_port,
ret = zfcp_fsf_req_send(req);
if (ret)
goto failed_send;
+ /* NOTE: DO NOT TOUCH req PAST THIS POINT! */
goto out;
@@ -1198,6 +1216,7 @@ int zfcp_fsf_send_els(struct zfcp_adapter *adapter, u32 d_id,
ret = zfcp_fsf_req_send(req);
if (ret)
goto failed_send;
+ /* NOTE: DO NOT TOUCH req PAST THIS POINT! */
goto out;
@@ -1243,6 +1262,7 @@ int zfcp_fsf_exchange_config_data(struct zfcp_erp_action *erp_action)
zfcp_fsf_req_free(req);
erp_action->fsf_req_id = 0;
}
+ /* NOTE: DO NOT TOUCH req PAST THIS POINT! */
out:
spin_unlock_irq(&qdio->req_q_lock);
return retval;
@@ -1279,8 +1299,10 @@ int zfcp_fsf_exchange_config_data_sync(struct zfcp_qdio *qdio,
zfcp_fsf_start_timer(req, ZFCP_FSF_REQUEST_TIMEOUT);
retval = zfcp_fsf_req_send(req);
spin_unlock_irq(&qdio->req_q_lock);
- if (!retval)
+ if (!retval) {
+ /* NOTE: ONLY TOUCH SYNC req AGAIN ON req->completion. */
wait_for_completion(&req->completion);
+ }
zfcp_fsf_req_free(req);
return retval;
@@ -1330,6 +1352,7 @@ int zfcp_fsf_exchange_port_data(struct zfcp_erp_action *erp_action)
zfcp_fsf_req_free(req);
erp_action->fsf_req_id = 0;
}
+ /* NOTE: DO NOT TOUCH req PAST THIS POINT! */
out:
spin_unlock_irq(&qdio->req_q_lock);
return retval;
@@ -1372,8 +1395,10 @@ int zfcp_fsf_exchange_port_data_sync(struct zfcp_qdio *qdio,
retval = zfcp_fsf_req_send(req);
spin_unlock_irq(&qdio->req_q_lock);
- if (!retval)
+ if (!retval) {
+ /* NOTE: ONLY TOUCH SYNC req AGAIN ON req->completion. */
wait_for_completion(&req->completion);
+ }
zfcp_fsf_req_free(req);
@@ -1493,6 +1518,7 @@ int zfcp_fsf_open_port(struct zfcp_erp_action *erp_action)
erp_action->fsf_req_id = 0;
put_device(&port->dev);
}
+ /* NOTE: DO NOT TOUCH req PAST THIS POINT! */
out:
spin_unlock_irq(&qdio->req_q_lock);
return retval;
@@ -1557,6 +1583,7 @@ int zfcp_fsf_close_port(struct zfcp_erp_action *erp_action)
zfcp_fsf_req_free(req);
erp_action->fsf_req_id = 0;
}
+ /* NOTE: DO NOT TOUCH req PAST THIS POINT! */
out:
spin_unlock_irq(&qdio->req_q_lock);
return retval;
@@ -1626,6 +1653,7 @@ int zfcp_fsf_open_wka_port(struct zfcp_fc_wka_port *wka_port)
retval = zfcp_fsf_req_send(req);
if (retval)
zfcp_fsf_req_free(req);
+ /* NOTE: DO NOT TOUCH req PAST THIS POINT! */
out:
spin_unlock_irq(&qdio->req_q_lock);
if (!retval)
@@ -1681,6 +1709,7 @@ int zfcp_fsf_close_wka_port(struct zfcp_fc_wka_port *wka_port)
retval = zfcp_fsf_req_send(req);
if (retval)
zfcp_fsf_req_free(req);
+ /* NOTE: DO NOT TOUCH req PAST THIS POINT! */
out:
spin_unlock_irq(&qdio->req_q_lock);
if (!retval)
@@ -1776,6 +1805,7 @@ int zfcp_fsf_close_physical_port(struct zfcp_erp_action *erp_action)
zfcp_fsf_req_free(req);
erp_action->fsf_req_id = 0;
}
+ /* NOTE: DO NOT TOUCH req PAST THIS POINT! */
out:
spin_unlock_irq(&qdio->req_q_lock);
return retval;
@@ -1899,6 +1929,7 @@ int zfcp_fsf_open_lun(struct zfcp_erp_action *erp_action)
zfcp_fsf_req_free(req);
erp_action->fsf_req_id = 0;
}
+ /* NOTE: DO NOT TOUCH req PAST THIS POINT! */
out:
spin_unlock_irq(&qdio->req_q_lock);
return retval;
@@ -1987,6 +2018,7 @@ int zfcp_fsf_close_lun(struct zfcp_erp_action *erp_action)
zfcp_fsf_req_free(req);
erp_action->fsf_req_id = 0;
}
+ /* NOTE: DO NOT TOUCH req PAST THIS POINT! */
out:
spin_unlock_irq(&qdio->req_q_lock);
return retval;
@@ -2299,6 +2331,7 @@ int zfcp_fsf_fcp_cmnd(struct scsi_cmnd *scsi_cmnd)
retval = zfcp_fsf_req_send(req);
if (unlikely(retval))
goto failed_scsi_cmnd;
+ /* NOTE: DO NOT TOUCH req PAST THIS POINT! */
goto out;
@@ -2373,8 +2406,10 @@ struct zfcp_fsf_req *zfcp_fsf_fcp_task_mgmt(struct scsi_device *sdev,
zfcp_fc_fcp_tm(fcp_cmnd, sdev, tm_flags);
zfcp_fsf_start_timer(req, ZFCP_FSF_SCSI_ER_TIMEOUT);
- if (!zfcp_fsf_req_send(req))
+ if (!zfcp_fsf_req_send(req)) {
+ /* NOTE: DO NOT TOUCH req, UNTIL IT COMPLETES! */
goto out;
+ }
zfcp_fsf_req_free(req);
req = NULL;
generated by cgit v1.2.3 (git 2.39.1) at 2025-01-04 12:47:54 +0100