[src/trunk]: src/sys/dev/i2c Add a kernel panic when we matched but can not h...

[martin <martin%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/9af539c7c859
branches:  trunk
changeset: 320081:9af539c7c859
user:      martin <martin%NetBSD.org@localhost>
date:      Fri Jun 22 15:48:57 2018 +0000

description:
Add a kernel panic when we matched but can not handle a string - better
die explicitly instead of crashing a few lines later with strange NULL
derefs.

diffstat:

 sys/dev/i2c/dbcool.c |  8 +++++---
 1 files changed, 5 insertions(+), 3 deletions(-)

diffs (31 lines):

diff -r a59908584d9e -r 9af539c7c859 sys/dev/i2c/dbcool.c
--- a/sys/dev/i2c/dbcool.c      Fri Jun 22 11:25:03 2018 +0000
+++ b/sys/dev/i2c/dbcool.c      Fri Jun 22 15:48:57 2018 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: dbcool.c,v 1.50 2018/06/18 17:07:07 thorpej Exp $ */
+/*     $NetBSD: dbcool.c,v 1.51 2018/06/22 15:48:57 martin Exp $ */
 
 /*-
  * Copyright (c) 2008 The NetBSD Foundation, Inc.
@@ -50,7 +50,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: dbcool.c,v 1.50 2018/06/18 17:07:07 thorpej Exp $");
+__KERNEL_RCSID(0, "$NetBSD: dbcool.c,v 1.51 2018/06/22 15:48:57 martin Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -779,9 +779,11 @@
        sc->sc_dc.dc_chip = NULL;
        sc->sc_dc.dc_readreg = dbcool_readreg;
        sc->sc_dc.dc_writereg = dbcool_writereg;
-       (void)dbcool_chip_ident(&sc->sc_dc);
        sc->sc_dev = self;
 
+       if (dbcool_chip_ident(&sc->sc_dc) < 0 || sc->sc_dc.dc_chip == NULL)
+               panic("could not identify chip at addr %d", args->ia_addr);
+
        aprint_naive("\n");
        aprint_normal("\n");