[S390] cio: fix use after free in s390 debug feature

When using s390dbf with "%s" in sprintf format strings the string itself
is not copied to the dbf buffer.
Since in this case only pointers are stored in the s390dbf, we should
not use dev_name - which is bound to the lifetime of the device.
Reading this entry from s390dbf after the device was released will cause
an use after free error.

Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

diff --git a/drivers/s390/cio/device.c b/drivers/s390/cio/device.c
index a50cfa51aa3cee6cd92cafcaba9e3ef2f9d8b5b7..6b770f8c0a8941105314e1d4c5baddb035473ee2 100644 (file)
--- a/drivers/s390/cio/device.c
+++ b/drivers/s390/cio/device.c
@@ -2038,7 +2038,9 @@ static void __ccw_device_pm_restore(struct ccw_device *cdev)
        spin_unlock_irq(sch->lock);
        if (ret) {
                CIO_MSG_EVENT(0, "Couldn't start recognition for device "
-                             "%s (ret=%d)\n", dev_name(&cdev->dev), ret);
+                             "0.%x.%04x (ret=%d)\n",
+                             cdev->private->dev_id.ssid,
+                             cdev->private->dev_id.devno, ret);
                spin_lock_irq(sch->lock);
                cdev->private->state = DEV_STATE_DISCONNECTED;
                spin_unlock_irq(sch->lock);
@@ -2101,8 +2103,9 @@ static int ccw_device_pm_restore(struct device *dev)
        }
        /* check if the device id has changed */
        if (sch->schib.pmcw.dev != cdev->private->dev_id.devno) {
-               CIO_MSG_EVENT(0, "resume: sch %s: failed (devno changed from "
-                             "%04x to %04x)\n", dev_name(&sch->dev),
+               CIO_MSG_EVENT(0, "resume: sch 0.%x.%04x: failed (devno "
+                             "changed from %04x to %04x)\n",
+                             sch->schid.ssid, sch->schid.sch_no,
                              cdev->private->dev_id.devno,
                              sch->schib.pmcw.dev);
                goto out_unreg_unlock;
@@ -2135,8 +2138,9 @@ static int ccw_device_pm_restore(struct device *dev)
        if (cm_enabled) {
                ret = ccw_set_cmf(cdev, 1);
                if (ret) {
-                       CIO_MSG_EVENT(2, "resume: cdev %s: cmf failed "
-                                     "(rc=%d)\n", dev_name(&cdev->dev), ret);
+                       CIO_MSG_EVENT(2, "resume: cdev 0.%x.%04x: cmf failed "
+                                     "(rc=%d)\n", cdev->private->dev_id.ssid,
+                                     cdev->private->dev_id.devno, ret);
                        ret = 0;
                }
        }