[LU-6519] potential null pointer dereference in class_newdev

• Type: Bug
• Resolution: Fixed
• Priority: Minor
• Fix Version/s: Lustre 2.11.0
• Labels: smatch
• Severity: 3
• Assignee: WC Triage
• Reporter: Oleg Drokin

Description

smatch highlighted this in class_newdev:

        if (result == NULL && i >= class_devno_max()) {
                CERROR("all %u OBD devices used, increase MAX_OBD_DEVICES\n",
                       class_devno_max());
                GOTO(out, result = ERR_PTR(-EOVERFLOW));
        }

        if (IS_ERR(result))
                GOTO(out, result);

        CDEBUG(D_IOCTL, "Adding new device %s (%p)\n",
               result->obd_name, result);

So this totally seems to assume that if result == NULL, but we did not go beyond the obd device limit, we are ok to print this NULL pointer?

I suspect we should chance the IS_ERRO to either result == NULL || IS_ERR?

Issue Links

• is related to: LU-4134 obdfilter-suvery bugs and panics (ioctl API isn't protected over shutdown/setup property).