[SCSI] zfcp: Fix oops when port disappears

The zfcp_port might have been removed, while the FC fast_io_fail timer
is still running and could trigger the terminate_rport_io callback.
Set the pointer to the zfcp_port to NULL and check accordingly
before using it.

Reviewed-by: Martin Petermann <martin@linux.vnet.ibm.com>
Signed-off-by: Christof Schmitt <christof.schmitt@de.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/drivers/s390/scsi/zfcp_fsf.c b/drivers/s390/scsi/zfcp_fsf.c
index 3f365ace7711..74dee32afba8 100644
--- a/drivers/s390/scsi/zfcp_fsf.c
+++ b/drivers/s390/scsi/zfcp_fsf.c
@@ -172,12 +172,16 @@ static void zfcp_fsf_link_down_info_eval(struct zfcp_fsf_req *req, char *id,
                                          struct fsf_link_down_info *link_down)
 {
         struct zfcp_adapter *adapter = req->adapter;
+        unsigned long flags;
 
         if (atomic_read(&adapter->status) & ZFCP_STATUS_ADAPTER_LINK_UNPLUGGED)
                 return;
 
         atomic_set_mask(ZFCP_STATUS_ADAPTER_LINK_UNPLUGGED, &adapter->status);
+
+        read_lock_irqsave(&zfcp_data.config_lock, flags);
         zfcp_scsi_schedule_rports_block(adapter);
+        read_unlock_irqrestore(&zfcp_data.config_lock, flags);
 
         if (!link_down)
                 goto out;