On Wed, 27 Jul 2016, co...@sdf.org wrote:

Log Message:
If we're going to check for a NULL pointer, do the check before we
dereference it (to get the lock address).


To generate a diff of this commit:
cvs rdiff -u -r1.76 -r1.77 src/sys/dev/md.c

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.


Modified files:

Index: src/sys/dev/md.c
diff -u src/sys/dev/md.c:1.76 src/sys/dev/md.c:1.77
--- src/sys/dev/md.c:1.76       Mon Jan  4 16:24:52 2016
+++ src/sys/dev/md.c    Wed Jul 27 01:09:44 2016
@@ -1,4 +1,4 @@
-/*     $NetBSD: md.c,v 1.76 2016/01/04 16:24:52 hannken Exp $  */
+/*     $NetBSD: md.c,v 1.77 2016/07/27 01:09:44 pgoyette Exp $ */

 /*
  * Copyright (c) 1995 Gordon W. Ross, Leo Weppelman.
@@ -40,7 +40,7 @@
  */

 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: md.c,v 1.76 2016/01/04 16:24:52 hannken Exp $");
+__KERNEL_RCSID(0, "$NetBSD: md.c,v 1.77 2016/07/27 01:09:44 pgoyette Exp $");

 #ifdef _KERNEL_OPT
 #include "opt_md.h"
@@ -414,13 +414,13 @@ mdstrategy(struct buf *bp)

        sc = device_lookup_private(&md_cd, MD_UNIT(bp->b_dev));

-       mutex_enter(&sc->sc_lock);
-
        if (sc == NULL || sc->sc_type == MD_UNCONFIGURED) {
                bp->b_error = ENXIO;
                goto done;
        }

+       mutex_enter(&sc->sc_lock);
+
        switch (sc->sc_type) {
 #if MEMORY_DISK_SERVER
        case MD_UMEM_SERVER:


goto done; will exit mutex not entered now, I think.

Yup - already fixed.



+------------------+--------------------------+------------------------+
| Paul Goyette     | PGP Key fingerprint:     | E-mail addresses:      |
| (Retired)        | FA29 0E3B 35AF E8AE 6651 | paul at whooppee.com   |
| Kernel Developer | 0786 F758 55DE 53BA 7731 | pgoyette at netbsd.org |
+------------------+--------------------------+------------------------+

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