On some architectures you can get away with using an uninitialised mutex;

this is not the case on hppa (practically the only architecture where
unlocked has a non-zero value). This one has been hiding since r1.223...

Found the hard way by juanfra@

diff --git a/sys/dev/softraid.c b/sys/dev/softraid.c
index 3aa4951..f876d75 100644 (file)
--- a/sys/dev/softraid.c
+++ b/sys/dev/softraid.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: softraid.c,v 1.314 2013/11/19 15:12:13 krw Exp $ */
+/* $OpenBSD: softraid.c,v 1.315 2014/01/05 15:03:57 jsing Exp $ */
 /*
  * Copyright (c) 2007, 2008, 2009 Marco Peereboom <marco@peereboom.us>
  * Copyright (c) 2008 Chris Kuethe <ckuethe@openbsd.org>
@@ -2120,6 +2120,7 @@ sr_wu_alloc(struct sr_discipline *sd)
 
        sd->sd_wu = malloc(sizeof(struct sr_workunit) * no_wu,
            M_DEVBUF, M_WAITOK | M_ZERO);
+       mtx_init(&sd->sd_wu_mtx, IPL_BIO);
        TAILQ_INIT(&sd->sd_wu_freeq);
        TAILQ_INIT(&sd->sd_wu_pendq);
        TAILQ_INIT(&sd->sd_wu_defq);
@@ -3466,7 +3467,6 @@ sr_ioctl_createraid(struct sr_softc *sc, struct bioc_createraid *bc,
                }
 
                /* Setup SCSI iopool. */
-               mtx_init(&sd->sd_wu_mtx, IPL_BIO);
                scsi_iopool_init(&sd->sd_iopool, sd, sr_wu_get, sr_wu_put);
 
                /*