Hi,
Yes it should be backported to stables. This bug existed for a while.
On Mon, Sep 23, 2013 at 5:29 AM, Jonghwan Choi <jhbird.choi@xxxxxxxxx> wrote:
> From: Anatol Pomozov <anatol.pomozov@xxxxxxxxx>
>
> This patch looks like it should be in the 3.11-stable tree, should we apply
> it?
>
> ------------------
>
> From: "Anatol Pomozov <anatol.pomozov@xxxxxxxxx>"
>
> commit f3cff25f05f2ac29b2ee355e611b0657482f6f1d upstream
>
> '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>
> Acked-by: Tejun Heo <tj@xxxxxxxxxx>
> Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
> Signed-off-by: Jonghwan Choi <jhbird.choi@xxxxxxxxxxx>
> ---
> 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;
> --
> 1.8.1.2
>
--
To unsubscribe from this list: send the line "unsubscribe stable" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html