Re: kern/42662: iop driver makes kernel crash or freeze

[Manuel Bouyer <bouyer%antioche.eu.org@localhost>]

The following reply was made to PR kern/42662; it has been noted by GNATS.

From: Manuel Bouyer <bouyer%antioche.eu.org@localhost>
To: Aleksej Saushev <asau%inbox.ru@localhost>
Cc: gnats-bugs%NetBSD.org@localhost, kern-bug-people%NetBSD.org@localhost, 
gnats-admin%NetBSD.org@localhost,
        netbsd-bugs%NetBSD.org@localhost
Subject: Re: kern/42662: iop driver makes kernel crash or freeze
Date: Sat, 30 Jan 2010 19:21:16 +0100

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 On Sat, Jan 30, 2010 at 06:42:37PM +0300, Aleksej Saushev wrote:
 > Manuel Bouyer <bouyer%antioche.eu.org@localhost> writes:
 > 
 > >  On Fri, Jan 22, 2010 at 05:50:01PM +0000, Aleksej Saushev wrote:
 > >  >         5.0_STABLE installation kernel panics when initializing iop 
 > > driver,
 > >  >         5.99.24 kernel as of 2009-01-21 crashes too,
 > >  >         5.99.24 kernel as of today doesn't crash, it freezes instead.
 > >  > 
 > >  >         All diagnostics below corresponds to 5.0_STABLE.
 > >  > 
 > >  >         Kernel message at panic:
 > >  > 
 > >  >         iop0 at pci3 dev 3 function 0: I2O adapterpanic: 
 > > _bus_dmamap_sync: mix PRE and POST
 > >  
 > >  Can you try the attached patch on netbsd-5 ?
 > >  No idea why it hangs on current, more info needed.
 > 
 > I applied it to the current instead, it crashes with the same diagnostic
 > message and similar backtrace, only it seems to do it a bit later.
 > I can try to replace as many instances of the pattern as needed,
 > can you recommend how many of them? All in that subroutine?
 
 All of them, mixing PRE and POST in bus_dma(9) is not allowed.
 I also found one mistake where a PRE should have been a POST.
 Please try the attached patch (still against netbsd-5).
 
 -- 
 Manuel Bouyer <bouyer%antioche.eu.org@localhost>
      NetBSD: 26 ans d'experience feront toujours la difference
 --
 
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 Index: iop.c
 ===================================================================
 RCS file: /cvsroot/src/sys/dev/i2o/iop.c,v
 retrieving revision 1.75
 diff -u -p -u -r1.75 iop.c
 --- iop.c      14 Sep 2008 18:12:16 -0000      1.75
 +++ iop.c      30 Jan 2010 18:19:36 -0000
 @@ -928,7 +928,7 @@ iop_status_get(struct iop_softc *sc, int
            BUS_DMASYNC_PREWRITE);
        memset(st, 0, sizeof(*st));
        bus_dmamap_sync(sc->sc_dmat, sc->sc_scr_dmamap, 0, sizeof(*st),
 -          BUS_DMASYNC_PREREAD|BUS_DMASYNC_POSTWRITE);
 +          BUS_DMASYNC_POSTWRITE);
  
        if ((rv = iop_post(sc, (u_int32_t *)&mf)) != 0)
                return (rv);
 @@ -993,7 +993,7 @@ iop_ofifo_init(struct iop_softc *sc)
            BUS_DMASYNC_PREWRITE);
        *sw = 0;
        bus_dmamap_sync(sc->sc_dmat, sc->sc_scr_dmamap, 0, sizeof(*sw),
 -          BUS_DMASYNC_PREREAD|BUS_DMASYNC_POSTWRITE);
 +          BUS_DMASYNC_POSTWRITE);
  
        if ((rv = iop_post(sc, mb)) != 0)
                return (rv);
 @@ -1550,7 +1550,7 @@ iop_reset(struct iop_softc *sc)
            BUS_DMASYNC_PREWRITE);
        *sw = htole32(0);
        bus_dmamap_sync(sc->sc_dmat, sc->sc_scr_dmamap, 0, sizeof(*sw),
 -          BUS_DMASYNC_PREWRITE|BUS_DMASYNC_PREREAD);
 +          BUS_DMASYNC_POSTWRITE);
  
        if ((rv = iop_post(sc, (u_int32_t *)&mf)))
                return (rv);
 
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