(cc'ing Jens)
Hello,
On Fri, Sep 13, 2013 at 09:20:45AM -0700, Anatol Pomozov wrote:
> Hi, Tejun
>
> On Fri, Aug 30, 2013 at 10:52 AM, Anatol Pomozov
> <anatol.pomozov@xxxxxxxxx> wrote:
> > 'samples' is 64bit operant, but do_div() second parameter is 32.
> > do_div silently truncates high 32 bits and calculated result
> > is invalid.
> >
> > In case if low 32bit of 'samples' are zeros then do_div() produces
> > kernel crash.
> >
> > Signed-off-by: Anatol Pomozov <anatol.pomozov@xxxxxxxxx>
> > ---
> > block/cfq-iosched.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
> > index d5bbdcf..c410752 100644
> > --- a/block/cfq-iosched.c
> > +++ b/block/cfq-iosched.c
> > @@ -1803,7 +1803,7 @@ static u64 cfqg_prfill_avg_queue_size(struct seq_file *sf,
> >
> > if (samples) {
> > v = blkg_stat_read(&cfqg->stats.avg_queue_size_sum);
> > - do_div(v, samples);
> > + v = div64_u64(v, samples);
> > }
> > __blkg_prfill_u64(sf, pd, v);
> > return 0;
>
> what do you think about this patch?
Sorry about the delay. Was traveling.
Acked-by: Tejun Heo <tj@xxxxxxxxxx>
blkcg patches are routed through Jens's block tree but I haven't been
able to get hold of Jens lately. Jens?
Thanks.
--
tejun
--
To unsubscribe from this list: send the line "unsubscribe cgroups" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
