On Monday November 3, maan@xxxxxxxxxxxxxxx wrote: > > This sector_div() is in linear_conf() while the call trace indicates > > the bug happens in mddev_put(). I'll have a deeper look later today. > > Indeed, this sector_div() is responsible for the bug. The following > patch (against Neil's for-next tree) should fix this. Please give it a > try. Thanks Andre. This is definitely a bug, since 2.6.14!! I'll queue that patch for mainline and -stable. Thanks, NeilBrown > > Andre > > commit 284b3e2a37c8790d0e9315aed03d594165a85455 > Author: Andre Noll <maan@xxxxxxxxxxxxxxx> > Date: Mon Nov 3 19:39:22 2008 +0100 > > md: linear: Fix a division by zero bug for very small arrays. > > We currently oops with a divide error on starting a linear software > raid array consisting of at least two very small (< 500K) devices. > > The bug is caused by the calculation of the hash table size which > tries to compute sector_div(sz, base) with "base" being zero due to > the small size of the component devices of the array. > > Fix this by requiring the hash spacing to be at least one which > implies that also "base" is non-zero. > > Signed-off-by: Andre Noll <maan@xxxxxxxxxxxxxxx> > > diff --git a/drivers/md/linear.c b/drivers/md/linear.c > index 190147c..3b90c5c 100644 > --- a/drivers/md/linear.c > +++ b/drivers/md/linear.c > @@ -148,6 +148,8 @@ static linear_conf_t *linear_conf(mddev_t *mddev, int raid_disks) > > min_sectors = conf->array_sectors; > sector_div(min_sectors, PAGE_SIZE/sizeof(struct dev_info *)); > + if (min_sectors == 0) > + min_sectors = 1; > > /* min_sectors is the minimum spacing that will fit the hash > * table in one PAGE. This may be much smaller than needed. > -- > The only person who always got his work done by Friday was Robinson Crusoe -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
